WO2017049521A1 - 同步方法、用户设备和基站 - Google Patents

同步方法、用户设备和基站 Download PDF

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Publication number
WO2017049521A1
WO2017049521A1 PCT/CN2015/090512 CN2015090512W WO2017049521A1 WO 2017049521 A1 WO2017049521 A1 WO 2017049521A1 CN 2015090512 W CN2015090512 W CN 2015090512W WO 2017049521 A1 WO2017049521 A1 WO 2017049521A1
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WO
WIPO (PCT)
Prior art keywords
synchronization
source
information
user equipment
synchronization signal
Prior art date
Application number
PCT/CN2015/090512
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English (en)
French (fr)
Inventor
黎超
张兴炜
冯淑兰
Original Assignee
华为技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP15904408.0A priority Critical patent/EP3340699A4/en
Priority to CN201580063534.1A priority patent/CN107005958B/zh
Priority to PCT/CN2015/090512 priority patent/WO2017049521A1/zh
Priority to CN202010512780.3A priority patent/CN111867043B/zh
Priority to CN202010513057.7A priority patent/CN111867044B/zh
Priority to KR1020187009583A priority patent/KR102147713B1/ko
Priority to JP2018513312A priority patent/JP6798668B2/ja
Publication of WO2017049521A1 publication Critical patent/WO2017049521A1/zh
Priority to US15/927,098 priority patent/US10820288B2/en
Priority to US17/035,735 priority patent/US11611945B2/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/001—Synchronization between nodes
    • H04W56/0015—Synchronization between nodes one node acting as a reference for the others
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—Synchronising arrangements
    • H04J3/0635—Clock or time synchronisation in a network
    • H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/004—Synchronisation arrangements compensating for timing error of reception due to propagation delay
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/18—Self-organising networks, e.g. ad-hoc networks or sensor networks
    • H04W84/22—Self-organising networks, e.g. ad-hoc networks or sensor networks with access to wired networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/04—Large scale networks; Deep hierarchical networks
    • H04W84/042—Public Land Mobile systems, e.g. cellular systems
    • H04W84/045—Public Land Mobile systems, e.g. cellular systems using private Base Stations, e.g. femto Base Stations, home Node B
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/02—Terminal devices

Definitions

  • the present invention relates to the field of communications, and in particular, to a synchronization method, a user equipment, and a base station.
  • a fundamental problem in vehicle-to-vehicle communication is how to achieve efficient communication between cars and vehicles in a variety of complex environments.
  • One of the most basic requirements for improving the communication efficiency of vehicles and vehicles is to maintain a certain degree of precision synchronization between vehicles. Thereby, the mutual interference of the vehicle and the vehicle communication can be reduced and the spectrum efficiency when the vehicle and the vehicle communicate can be improved.
  • the embodiment of the invention provides a synchronization method, a user equipment and a base station, which can determine a synchronization reference source according to the synchronization information, thereby enabling synchronization.
  • a synchronization method including: acquiring, by a user equipment, synchronization information, where the synchronization information includes at least one of: selection parameter information of a synchronization source, indication information of a synchronization source, and priority of a synchronization source And the user equipment receives the first synchronization signal sent by the at least one synchronization source; the user equipment determines the synchronization reference source according to the synchronization information and the first synchronization signal.
  • the determining, by the user equipment, the synchronization reference source according to the synchronization information and the first synchronization signal includes: the user equipment selecting, according to the first synchronization signal, A synchronization source that satisfies the selection parameter among the at least one synchronization source is used as the synchronization reference source.
  • the indication information of the synchronization source is used to indicate a first synchronization source
  • the user equipment determines a synchronization reference source according to the synchronization information and the first synchronization signal.
  • the user equipment selects the first same according to the first synchronization signal
  • the step source is the synchronous reference source.
  • the determining, by the user equipment, the synchronization reference source according to the synchronization information and the first synchronization signal includes: the user equipment according to the priority information, The first synchronization signal selects the synchronization source with the highest priority among the at least one synchronization source as the synchronization reference source.
  • the indication information of the synchronization source is used to indicate a first synchronization source
  • the user equipment determines a synchronization reference source according to the synchronization information and the first synchronization signal.
  • the user equipment determines, according to the first synchronization signal, that the at least one synchronization source includes the first synchronization source; if the first synchronization source meets a predefined condition, the user equipment selects the The first synchronization source is the synchronization reference source; or, if the signal of the first synchronization source does not meet the predefined condition, the user equipment selects the first one of the at least one synchronization source according to the priority information.
  • the second synchronization source with the highest priority outside the synchronization source is the synchronization reference source.
  • the first synchronization signal includes a second synchronization signal and/or a third synchronization signal
  • the user equipment determining the synchronization reference source according to the synchronization information, comprising: the user equipment determining the at least one according to a sequence of the second synchronization signal and/or a sequence of the third synchronization signal a type of synchronization source; the user equipment selects the synchronization reference source according to the synchronization information and the at least one synchronization source type.
  • the first sequence, the second sequence, and the third sequence of the second synchronization signal are respectively used to indicate different synchronization source types, The first sequence, the second sequence, and the third sequence are different from each other; or
  • the second synchronization signal occupies a first symbol and a second symbol, and a plurality of combinations of the sequence used by the first symbol and the sequence used by the second symbol are used to indicate different synchronization source types; or
  • the sequence set of the third synchronization signal includes a plurality of sequence subsets, the plurality of sequence subsets being used to indicate different synchronization source types; or
  • the third synchronization signal occupies a third symbol and a fourth symbol, and a plurality of combinations of the sequence used by the third symbol and the sequence used by the fourth symbol are used to indicate different synchronization source types; or
  • the second synchronization signal occupies a first symbol and a second symbol
  • the third synchronization signal occupies a a three symbol and a fourth symbol, a sequence of the first symbol used, a sequence used by the second symbol, a sequence used by the third symbol, and a plurality of combinations of sequences used by the fourth symbol are used to indicate Different sync source types.
  • the method further includes: the user equipment receiving the at least one synchronization source to send Determining a synchronization reference source according to the synchronization information and the first synchronization signal, the user equipment determining, according to the first control information, a type of the at least one synchronization source; The user equipment determines the synchronization reference source according to the synchronization information, the first synchronization signal, and a type of the at least one synchronization source.
  • the method further includes: the user equipment receiving the at least one synchronization source
  • the first control information that is sent, the first control information includes at least one of the following information: type auxiliary indication information of the synchronization source, indication information of a transmission period of the synchronization signal, indication information of whether the synchronization signal is transmitted, and whether the synchronization signal is The effective indication information, the indication information of the time-frequency position of the synchronization signal transmission, and the indication information of the hop count of the synchronization source.
  • the first synchronization signal includes a second synchronization signal and/or a third synchronization signal
  • the user equipment determines, according to the first control information,
  • the type of the at least one synchronization source comprising: the user equipment determining the at least one synchronization source according to a sequence of the second synchronization signal and/or a sequence of the third synchronization signal, and the first control information type.
  • the receiving end acquires the synchronization information, that the user equipment receives the synchronization information that is sent by the base station.
  • the method before the user equipment receives the synchronization information, the method further includes: the user equipment sending the at least the a synchronization source information, so that the base station determines the synchronization information according to the information of the at least one synchronization source.
  • the user equipment that: sending, by the user equipment, the fourth synchronization signal and/or the second control information according to the synchronization reference source
  • the fourth synchronization signal and/or the second control information is used to indicate the type of the synchronization reference source.
  • the method further includes: determining, by the user equipment, a timing reference of the synchronization reference source and a synchronization reference source of another link Timing deviation between timing references; the user equipment communicates based on the timing reference of the synchronization reference source and the timing offset.
  • the user equipment determines a timing between a timing reference of the synchronization reference source and a timing reference of a synchronization reference source of another link
  • the deviation includes: the user equipment receives timing deviation indication information sent by the base station, the timing deviation indication is used to indicate the timing deviation shown; and the user equipment determines the timing deviation according to the timing deviation indication information.
  • the user equipment determines a timing between a timing reference of the synchronization reference source and a timing reference of a synchronization reference source of another link Deviating, comprising: a timing reference of the user equipment acquiring a synchronization reference source of the another link; the user equipment according to a timing reference of the synchronization reference source and a timing reference of a synchronization reference source of the another link The timing deviation is determined.
  • a synchronization method including: determining, by a base station, synchronization information, where the synchronization information includes at least one of: selection parameter information of a synchronization source, indication information of a synchronization source, and priority information of a synchronization source
  • the base station transmits the synchronization information to the user equipment.
  • the method further includes: the base station sending, to the user equipment, control information, where the control information is used to indicate a type of the synchronous reference source and/or Or logo.
  • the method further includes: the base station sending control information to the user equipment, where the control information includes at least one of the following information: a synchronization source
  • the control information includes at least one of the following information: a synchronization source
  • the type assistance indication information the indication information of the transmission cycle of the synchronization signal, the indication information indicating whether the synchronization signal is valid, the indication information of whether the synchronization signal is transmitted, the indication information of the time-frequency position of the synchronization signal transmission, and the indication information of the hop count of the synchronization source.
  • the determining, by the base station, the synchronization information includes: the base station receiving the user Information of at least one synchronization source transmitted by the device; the base station determining the synchronization information according to information of the at least one synchronization source.
  • the method further includes: the base station sending a timing offset to the user equipment Instructing information, the timing deviation indication information is used to indicate a timing offset between a timing reference of a synchronization reference source of the user equipment and a timing reference of a synchronization reference source of another link.
  • a synchronization method including: determining, by a user equipment, a synchronization reference source, where the type of the synchronization reference source is any one of a global satellite navigation system, a base station, and a user equipment; Synchronizing the reference source to transmit a synchronization signal, the synchronization signal comprising a first synchronization signal and/or a second synchronization signal, the sequence of the first synchronization signal and/or the sequence of the second synchronization signal being used to indicate the synchronization reference The type of source.
  • the at least one sequence of the first synchronization signal is used to indicate a type of the synchronization reference source
  • the first synchronization signal occupies a first symbol and a second symbol, and at least one combination of a sequence used by the first symbol and a sequence used by the second symbol is used to indicate a type of the synchronization reference source; or ,
  • the sequence set of the second synchronization signal includes at least two sequence subsets, and at least one subset of the at least two sequence subsets is used to indicate a type of the synchronization reference source; or
  • the second synchronization signal includes a third symbol and a fourth symbol, and at least one combination of a sequence used by the third symbol and a sequence used by the fourth symbol is used to indicate a type of the synchronization reference source; or ,
  • the first synchronization signal occupies a first symbol and a second symbol
  • the second synchronization signal occupies a third symbol and a fourth symbol
  • a sequence used by the first symbol a sequence used by the second symbol
  • the At least one combination of the sequence used by the third symbol and the sequence used by the fourth symbol is used to indicate the type of the synchronization reference source.
  • the method further includes: the user equipment sends control information, a sequence of the first synchronization signal And/or a sequence of the second synchronization signal, and the control information is used to indicate the type of the synchronization reference source.
  • the user equipment sends control information, where the control information includes at least one of the following information Kind: type auxiliary indication information of the synchronization source, indication information of the transmission period of the synchronization signal, indication information of whether the synchronization signal is valid, indication information of whether the synchronization signal is transmitted, indication information of the time-frequency position of the synchronization signal transmission, and jump of the synchronization source The number of instructions.
  • a fourth aspect provides a user equipment, including: an acquiring unit, configured to acquire synchronization information, where The synchronization information includes at least one of the following: the selection parameter information of the synchronization source, the indication information of the synchronization source, and the priority information of the synchronization source; the transceiver unit, configured to receive the first synchronization signal of the at least one synchronization source; And a unit, configured to determine a synchronization reference source according to the synchronization information acquired by the acquiring unit and the first synchronization signal received by the transceiver unit.
  • the determining unit is specifically configured to: select, according to the first synchronization signal, a synchronization source that meets the selection parameter among the at least one synchronization source As the synchronous reference source.
  • the indication information of the synchronization source is used to indicate a first synchronization source, and the determining unit is specifically configured to select according to the first synchronization signal.
  • the first synchronization source is the synchronization reference source.
  • the determining unit is specifically configured to: the user equipment select the at least one synchronization according to the priority information and the first synchronization signal
  • the synchronization source with the highest priority among the sources is the synchronization reference source.
  • the indication information of the synchronization source is used to indicate a first synchronization source
  • the determining unit is specifically configured to: determine, according to the first synchronization signal Include the first synchronization source in the at least one synchronization source; select the first synchronization source as the synchronization reference source if the first synchronization source satisfies a predefined condition; or if the first synchronization The source signal does not satisfy the predefined condition, and the second synchronization source having the highest priority among the at least one synchronization source except the first synchronization source is selected as the synchronization reference source according to the priority information.
  • the first synchronization signal The second synchronizing signal and/or the third synchronizing signal, the determining unit is configured to: determine the type of the at least one synchronization source according to the sequence of the second synchronizing signal and/or the sequence of the third synchronizing signal Selecting the synchronization reference source according to the synchronization information and the type of the at least one synchronization source.
  • the first sequence, the second sequence, and the third sequence of the second synchronization signal are used to indicate Different synchronization source types, the first sequence, the second sequence, and the third sequence are different from each other; or
  • the second synchronization signal occupies a first symbol and a second symbol, and the sequence used by the first symbol And various combinations of sequences used by the second symbol are used to indicate different synchronization source types; or,
  • the sequence set of the third synchronization signal includes a plurality of sequence subsets, the plurality of sequence subsets being used to indicate different synchronization source types; or
  • the third synchronization signal occupies a third symbol and a fourth symbol, and a plurality of combinations of the sequence used by the third symbol and the sequence used by the fourth symbol are used to indicate different synchronization source types; or
  • the second synchronization signal occupies a first symbol and a second symbol
  • the third synchronization signal occupies a third symbol and a fourth symbol
  • a sequence used by the first symbol a sequence used by the second symbol
  • the Various combinations of the sequence used by the third symbol and the sequence used by the fourth symbol are used to indicate different synchronization source types.
  • the transceiver unit is further configured to: Receiving, by the at least one synchronization source, the first control information, where the determining unit is configured to: determine, according to the first control information, a type of the at least one synchronization source; according to the synchronization information, the first The synchronization signal and the type of the at least one synchronization source determine the synchronization reference source.
  • the transceiver unit is further used Receiving, by the at least one synchronization source, first control information, where the first control information includes at least one of the following information: type auxiliary indication information of the synchronization source, indication information of a transmission period of the synchronization signal, and whether the synchronization signal is The indication information to be transmitted, the indication information indicating whether the synchronization signal is valid, the indication information of the time-frequency position of the synchronization signal transmission, and the indication information of the hop count of the synchronization source.
  • the first control information includes at least one of the following information: type auxiliary indication information of the synchronization source, indication information of a transmission period of the synchronization signal, and whether the synchronization signal is The indication information to be transmitted, the indication information indicating whether the synchronization signal is valid, the indication information of the time-frequency position of the synchronization signal transmission, and the indication information of the hop count of the synchronization source.
  • the first synchronization signal includes a second synchronization signal and/or a third synchronization signal
  • the determining unit Specifically, determining, according to the sequence of the second synchronization signal and/or the sequence of the third synchronization signal, and the first control information, a type of the at least one synchronization source.
  • the acquiring unit is specifically configured to: receive the synchronization information that is sent by the base station.
  • the transceiver unit is further configured to: before the acquiring unit receives the synchronization information, send information of the at least one synchronization source to the base station, so that the base station is configured according to the at least one synchronization source. The information determines the synchronization information.
  • the transceiver unit is further configured to send a fourth according to the synchronization reference source a synchronization signal and/or second control information, the fourth synchronization signal and/or the second control information being used to indicate the type of the synchronization reference source.
  • the determining unit is further configured to determine a timing reference of the synchronous reference source a timing offset between a timing reference of a synchronization reference source of another link; the transceiver unit is further configured to communicate according to the timing reference of the synchronization reference source and the timing offset determined by the determining unit.
  • the transceiver unit is further configured to receive timing deviation indication information sent by the base station, where the timing deviation is The indication is used to indicate the timing deviation shown; the determining unit is specifically configured to determine the timing deviation according to the timing deviation indication information received by the transceiver unit.
  • the acquiring unit is further configured to acquire a timing of the synchronization reference source of the another link
  • the determining unit is specifically configured to determine the timing offset according to a timing reference of the synchronization reference source and a timing reference of a synchronization reference source of the another link.
  • a fifth aspect provides a base station, comprising: a determining unit, configured to determine synchronization information, where the synchronization information includes at least one of the following: a selection parameter information of a synchronization source, indication information of a synchronization source, and a synchronization source. Priority information; a sending unit, configured to send the synchronization information to the user equipment.
  • the sending unit is further configured to: send, to the user equipment, control information, where the control information is used to indicate a type of the synchronous reference source And / or identification.
  • the method further includes: the base station sending the control information to the user equipment, where the control information includes at least one of the following information: The indication information, the indication information of the transmission cycle of the synchronization signal, the indication information of whether the synchronization signal is valid, the indication information of whether the synchronization signal is transmitted, and the time-frequency bit of the synchronization signal transmission The indication information of the setting information and the hop count of the synchronization source.
  • the method further includes: a receiving unit, Receiving, by the user equipment, the information of the at least one synchronization source that is sent by the user equipment, where the determining unit is configured to determine, according to the information of the at least one synchronization source received by the receiving unit, Synchronization information.
  • the sending unit is further configured to send the timing deviation indication information to the user equipment, where
  • the timing deviation indication information is used to indicate a timing offset between a timing reference of a synchronization reference source of the user equipment and a timing reference of a synchronization reference source of another link.
  • a user equipment including: a determining unit, configured to determine a synchronization reference source, where the type of the synchronization reference source is any one of a global satellite navigation system, a base station, and a user equipment; And transmitting a synchronization signal according to the synchronization reference source, the synchronization signal includes a first synchronization signal and/or a second synchronization signal, and a sequence of the first synchronization signal and/or a sequence of the second synchronization signal is used to indicate The type of synchronization reference source.
  • the at least one sequence of the first synchronization signal is used to indicate a type of the synchronization reference source
  • the first synchronization signal occupies a first symbol and a second symbol, and at least one combination of a sequence used by the first symbol and a sequence used by the second symbol is used to indicate a type of the synchronization reference source; or ,
  • the sequence set of the second synchronization signal includes at least two sequence subsets, and at least one subset of the at least two sequence subsets is used to indicate a type of the synchronization reference source; or
  • the second synchronization signal includes a third symbol and a fourth symbol, and at least one combination of a sequence used by the third symbol and a sequence used by the fourth symbol is used to indicate a type of the synchronization reference source; or ,
  • the first synchronization signal occupies a first symbol and a second symbol
  • the second synchronization signal occupies a third symbol and a fourth symbol
  • a sequence used by the first symbol a sequence used by the second symbol
  • the At least one combination of the sequence used by the third symbol and the sequence used by the fourth symbol is used to indicate the type of the synchronization reference source.
  • the sending unit is further configured to send control information, the first synchronization A sequence of signals and/or a sequence of the second synchronization signals, and the control information is used to indicate the type of the synchronization reference source.
  • the sending unit is further configured to send control information, where the control information includes the following information At least one of: type assistance indication information of the synchronization source, indication information of a transmission cycle of the synchronization signal, indication information indicating whether the synchronization signal is valid, indication information of whether the synchronization signal is transmitted, indication information of a time-frequency position of the synchronization signal transmission, Indicates the number of hops of the synchronization source.
  • the synchronization reference source is determined according to the synchronization information and the synchronization signal transmitted by the at least one synchronization source, and synchronization can be achieved.
  • Figure 1 is a schematic diagram of vehicle communication.
  • FIG. 2A is a schematic diagram of a system architecture in accordance with an embodiment of the present invention.
  • 2B is a schematic diagram of another system architecture according to an embodiment of the present invention.
  • FIG. 3 is a schematic flowchart of a synchronization method according to an embodiment of the present invention.
  • FIG. 4 is a schematic flow chart of a synchronization method according to another embodiment of the present invention.
  • Figure 5 is a schematic diagram of a synchronization signal in accordance with an embodiment of the present invention.
  • FIG. 6 is a schematic diagram of another system architecture according to an embodiment of the present invention.
  • FIG. 7 is a schematic diagram of timing offsets of a cellular link and a device-to-device link in accordance with an embodiment of the present invention.
  • FIG. 8 is a schematic flowchart of a synchronization method according to still another embodiment of the present invention.
  • FIG. 9 is a schematic flowchart of a synchronization method according to still another embodiment of the present invention.
  • FIG. 10 is a schematic block diagram of a user equipment according to an embodiment of the present invention.
  • FIG. 11 is a schematic block diagram of a base station according to an embodiment of the present invention.
  • FIG. 12 is a schematic block diagram of a user equipment according to another embodiment of the present invention.
  • FIG. 13 is a schematic block diagram of a user equipment according to another embodiment of the present invention.
  • FIG. 14 is a schematic block diagram of a base station according to another embodiment of the present invention.
  • FIG. 15 is a schematic block diagram of a user equipment according to another embodiment of the present invention.
  • the synchronization source may be an Evolved Node B (eNB), or may be from a Global Navigation Satellite System (GNSS), or may be a user equipment ( User Equipment, referred to as UE itself.
  • eNB Evolved Node B
  • GNSS Global Navigation Satellite System
  • UE User Equipment
  • the user equipment includes but is not limited to an in-vehicle device, a mobile station (Mobile Station, MS for short), a mobile terminal (Mobile Terminal), a mobile phone (Mobile Telephone), and a mobile phone (handset). ) and portable equipment.
  • the UE may also be a Road Side Unit (RSU) having an in-vehicle device function.
  • RSU Road Side Unit
  • the base station may be a Base Transceiver Station (BTS) in GSM or CDMA, or may be a base station (NodeB, NB for short) in WCDMA, or may be an evolved Node B (eNB) in LTE.
  • BTS Base Transceiver Station
  • NodeB, NB for short may be a base station (NodeB, NB for short) in WCDMA, or may be an evolved Node B (eNB) in LTE.
  • eNB evolved Node B
  • the base station can also be an RSU with base station functionality.
  • the base station is also referred to as a network, and is not limited in the present invention.
  • a base station or an eNB is used as an example for description.
  • GNSS Global Navigation Satellite System
  • Synchronization source refers to the synchronization source directly synchronized by the synchronous receiver, such as GNSS, eNB, UE, where GNSS, eNB and UE can be regarded as different external reference sources or independent reference sources;
  • Synchronization reference source or timing source refers to the type of synchronization source or timing referenced by a UE when it sends a synchronization signal to the outside, including: GNSS, eNB, UE.
  • the reference source at this time can be regarded as a non-independent reference source. The difference is that the synchronization source type and/or the number of hops forwarded are different when the UE sends the synchronization signal.
  • Synchronization signal The characteristics of the synchronization signal are different depending on the synchronization source.
  • the synchronization signal is one or more of downlink physical signals transmitted from the eNB.
  • the synchronization signal is a signal sent from the UE for detection and synchronization by other receiver UEs, including a synchronization signal between devices.
  • the synchronization source is GNSS
  • the synchronization signal is a predefined synchronization signal transmitted by satellite systems of various standards, so that the module of the satellite receiver can receive and implement time-frequency synchronization, timing, positioning and the like.
  • system architecture 200 includes:
  • UE1, UE2, UE3 Multiple user equipments (UE1, UE2, UE3), which can communicate with each other;
  • One or more base stations that can communicate with respective user equipment and/or RSUs;
  • GNSS Global Navigation Satellite Systems
  • UE1 and UE2 have the maximum relative moving speed when the vehicle moves at a high speed and UE1 and UE2 work relatively.
  • Each of the above user equipments can communicate with each other, and the spectrum of the cellular link can be used for communication, and the intelligent traffic spectrum near 5.9 GHz can also be used.
  • the technology for the communication between the user equipments can be enhanced based on the LTE protocol, and can be enhanced based on the D2D technology, which is not limited by the embodiment of the present invention.
  • FIG. 2B is a schematic diagram of a scenario of multiple types of synchronization sources according to an embodiment of the invention.
  • UE4, UE5, and UE6 can only detect the synchronization source transmitted from the UE.
  • UE4 can detect synchronization sources from UE1, UE2 and UE7.
  • the synchronization reference source of UE1 is GNSS.
  • UE1 needs to indicate to its receiver that its synchronization reference source type is GNSS, and when it sends out, it indicates that its hop count is The first hop (assuming that the hop count from GNSS to UE1 is the 0th hop).
  • UE7 is a synchronization source that is sent out on its own timing reference. At this time, its timing reference is generated based on local devices such as local crystal oscillator of UE7.
  • FIG. 3 is a schematic flow diagram of a synchronization method 300 in accordance with one embodiment of the present invention. As shown in FIG. 3, the synchronization method 300 includes the following.
  • the UE acquires synchronization information, where the synchronization information includes at least one of the following: the selection parameter information of the synchronization source, the indication information of the synchronization source, and the priority information of the synchronization source.
  • the selection parameter information of the synchronization source may include at least one of the following: a type of the synchronization source, a threshold value of the signal quality of the synchronization source, a threshold value of the hop count of the synchronization source, a threshold value of detecting/searching the duration of the synchronization source, The stability threshold of the synchronization source.
  • the signal quality includes Reference Signal Received Power (RSRP), and the reference signal reception quality. (Reference Signal Received Quality, RSF for short), at least one of Received Signal Strength Indication (RSSI).
  • the UE receives a first synchronization signal sent by at least one synchronization source.
  • the UE receives the first synchronization signal sent by each of the at least one synchronization source.
  • the at least one synchronization source may comprise a synchronization source of a GNSS, eNB or UE type, the at least one synchronization source may also comprise multiple types of synchronization sources.
  • the UE may receive the synchronization signal sent by the eNB and the GNSS; in the application scenario without network coverage, the UE may receive the synchronization signal sent by the GNSS; In the scenario, the UE may receive the synchronization signal sent by the UE.
  • the UE determines a synchronization reference source according to the synchronization information and the first synchronization signal.
  • the synchronization reference source may be one of the at least one synchronization source detected by the UE in step 320.
  • the embodiment of the present invention is not limited to this.
  • the synchronization reference source is the UE itself.
  • the UE may synchronize with the synchronization reference source according to the synchronization signal of the synchronization reference source.
  • the UE can communicate with other devices. For example, the UE can communicate with the synchronization reference source or base station or other UE.
  • the synchronization reference source is determined according to the synchronization information and the synchronization signal sent by the at least one synchronization source, and synchronization can be implemented.
  • the UE when the at least one synchronization source detected by the UE includes multiple types of synchronization sources, the UE can determine the synchronization reference source from multiple types of synchronization sources according to the synchronization information.
  • step 310 may include: receiving, by the UE, synchronization information sent by the base station.
  • the synchronization information may be carried in signaling (such as a broadcast message or a proprietary message) sent by the base station.
  • the synchronization information may be sent by the base station, but the embodiment of the present invention is not limited thereto.
  • the synchronization information may also be pre-configured on the UE, or may be predefined by a protocol.
  • the method 300 may further include:
  • the UE transmits information of at least one synchronization source to the base station, so that the base station determines the synchronization information according to the information of the at least one synchronization source.
  • the UE may report its detected first The information of the step source, after receiving the report of the UE, the base station sends synchronization information to the UE. Type and corresponding signal quality.
  • the information of the synchronization source may include at least one of the following types: a type of the synchronization source, a signal quality, and a hop count.
  • the signal quality of the synchronization source may include at least one of the following: RSRP of the synchronization source, RSRQ, RSSI, stability of the synchronization source signal, stabilization time of the synchronization reference source, and search time of the synchronization source.
  • the method by which the UE determines the type of the synchronization source can refer to the corresponding content described below. To avoid repetition, it will not be described in detail here.
  • the synchronization information may be pre-configured on the UE, or may be delivered to the UE by the base station, or may be delivered to the UE after receiving the information reported by the UE.
  • the synchronization information may include selection parameter information of the synchronization source.
  • the step 330 includes: the UE selecting, according to the first synchronization signal, a synchronization source that satisfies the selection parameter information among the at least one synchronization source as the synchronization reference source.
  • the selection parameter information may include: the synchronization reference source needs to meet (eg, higher or lower than) the threshold value of the corresponding signal quality, or the detection/search time of the synchronization reference source is lower than the corresponding threshold, or The stability of the synchronous reference source satisfies predefined conditions and the like.
  • the UE needs to detect the signal quality of the at least one synchronization source, and then select the synchronization reference source according to the selection parameter of the synchronization source.
  • the synchronization information may include indication information of a synchronization source, where the indication information of the synchronization source is used to indicate the first synchronization source.
  • the indication information of the synchronization source includes at least one of the following information: identification information of the synchronization source, type information of the synchronization source, and current hop count information of the synchronization source.
  • step 330 includes: the UE selecting the first synchronization source as the synchronization reference source according to the first synchronization signal.
  • the base station can specify a synchronization reference source for the UE.
  • the synchronization reference source of the UE is actually selected by the base station. Since the information on the base station side is the most secure, the embodiment of the present invention facilitates making an optimal decision.
  • the synchronization information includes priority information of the synchronization source.
  • the step 330 includes: the UE selecting, as the synchronization reference source, the synchronization source with the highest priority among the at least one synchronization source according to the priority information and the first synchronization signal.
  • the priority information of the synchronization source may include at least one of the following: priority information of the type of the synchronization source, priority information of the signal quality of the synchronization source, and priority information of the hop count of the synchronization source.
  • the priority information of the type of the synchronization source is used to indicate which synchronization source has the highest priority or the priority of the various synchronization sources.
  • the priority of the synchronization source may be GNSS>eNB>UE, and may also be an eNB. >GNSS>UE.
  • the priority information of the synchronization source may also be an indication of the ordering between the UE synchronization source, the GNSS, and the eNB of different hops.
  • GNSS>UE GNSS hop count is 1)>eNB>UE (eNB hop count is 1) or eNB>UE (eNB hop count is 1)>GNSS>UE (GNSS hop count is 1). I will not list them here.
  • the priority information of the signal quality of the synchronization source may indicate that the synchronization source with good signal quality is the preferred synchronization reference source, and the priority information of the hop count of the synchronization source may indicate that the synchronization source with the least number of hops is the preferred synchronization reference source.
  • the priority information of the synchronization source may include one priority information, and may also include various priority information.
  • the filtering condition may be used in the order of the defined various priorities, and the synchronous reference source is selected in steps.
  • the UE may first select the synchronization reference source according to the priority C1 as the judgment condition, and further select the synchronization reference source with the priority C2 as the judgment condition, and the priority C3 further selects the synchronization reference source as the judgment condition. In the above three steps, any one of the steps selects the determined synchronization source, and the synchronization reference source selection is considered successful. If the previous condition is not successfully selected, then continue to select the subsequent priority information until the determined synchronization reference source is selected.
  • the UE may perform layer-by-layer screening according to multiple priority information in a certain order to determine a synchronization source as a synchronization reference source. .
  • a synchronization source may be further selected as the synchronization reference source according to the second priority information.
  • the selection may continue to be continued or randomly selected according to other priority information, and details are not described herein again.
  • the sequence of the multiple priority information used by the UE to select the synchronization reference source in the embodiment of the present invention is not limited.
  • the UE may also select the finally used synchronization reference source in a random manner.
  • the UE detects the M1 synchronization sources, and first selects the synchronization source of the M2 eNBs from the M1 synchronization sources according to the priority information of the type of the synchronization source, for example, eNB>GNSS>UE; A synchronization source whose signal quality satisfies a predefined condition is selected from the M2 synchronization sources as a synchronization reference source.
  • the UE may further obtain the M3 synchronization sources.
  • a synchronization source with the least number of hops forwarded by the UE is selected as the synchronization reference source.
  • the synchronization reference source of the UE1 is a GNSS. If the synchronization reference source used by the UE2 is also a GNSS, the UE4 receives the synchronization information sent by the UE1 and the UE2 because the synchronization reference source is the same. It can be selected based on the number of hops and signal quality. The number of hops here is exactly the same, and it can also be selected according to the signal quality. For example, if the loss of UE1 to UE4 is smaller, UE4 can select UE1 as its own synchronization source.
  • UE5 can receive synchronization information sent from UE2, UE4 and UE6, and UE5 needs to select a synchronization source from UE2, UE4 and UE6 as the synchronization reference source. If the criterion of the minimum number of hops is used, UE2 can be selected as its own synchronization source (if UE2 selects GNSS or eNB as its own synchronization source).
  • step 330 can include:
  • the UE selects the first synchronization source as a synchronization reference source;
  • the UE selects the second synchronization source with the highest priority among the at least one synchronization source except the first synchronization source as the synchronization reference source according to the priority information.
  • the condition of the predetermined instrument may include at least one of the following: the signal quality of the second synchronization source satisfies a preset threshold, the hop count of the second synchronization source satisfies a preset threshold, and the detection of the second synchronization source/ The search duration meets the preset threshold, and the type of the second synchronization source is a preset type.
  • the pre-defined conditions may be pre-configured on the UE, or may be carried in the synchronization information, or may be acquired by the UE in other manners, which is not limited in this embodiment of the present invention.
  • the priority information may be pre-configured on the UE, or may be carried in the synchronization information, or may be acquired by the UE in other manners, which is not limited by the embodiment of the present invention.
  • the UE when the UE detects multiple and multiple synchronization sources from different types, the UE first determines whether the GNSS is detected; if the detected GNSS signal satisfies the predefined condition, the UE directly sends the GNSS as the synchronization reference source. Synchronize the signal and indicate to its receiver that the synchronization reference source used is GNSS and indicates the number of hops of the synchronization source it sends.
  • the other synchronization source detected by the UE or the synchronization source/synchronous reference source type, signal quality, hop count, etc. forwarded by the UE are viewed, according to the priority.
  • Information to select a synchronization reference source For the description of selecting the synchronization reference source according to the priority information, reference may be made to the above, and details are not described herein again.
  • GNSS is the preferred synchronization source. Applicable to the outside of the network, and/or the eNB in the network configures the GNSS as the preferred synchronization source.
  • Step 1 If the obtained synchronization information indicates that it is preferred to use GNSS as the synchronization source. Then when the receiver detects multiple and multiple sources from different types of synchronization sources, the receiver first determines if it has detected the GNSS and whether the detected GNSS meets the predefined conditions.
  • Step 2 If the detected GNSS signal satisfies a predefined condition, the receiver directly uses the GNSS as a synchronous reference source and transmits the synchronization signal outward. And indicate to its receiver that the synchronization reference source used is GNSS and indicates the number of synchronization source hops it is transmitting.
  • Step 3 If no GNSS is detected, or if the detected GNSS signal does not meet the predefined condition, then look at the synchronization source/synchronous reference source type, signal quality, hop count, etc. that other UEs have detected.
  • the synchronization source is selected according to the following criteria (the synchronization source at this time may include GNSS and UE, and the timing reference source forwarded by the UE may include one of eNB, GNSS, UE):
  • the first priority of the synchronization source type, the signal quality is the second priority, and the hop count is the third priority:
  • the UE simultaneously receives synchronization reference sources forwarded by multiple UEs, which are respectively from the synchronization reference source of the M1 eNBs, the synchronization reference source of the M2 GNSSs, and the synchronization reference source of the M3 UEs.
  • the type of the synchronization reference source is the first priority, and the order of the priority is GNSS>eNB>UE, find the M21 synchronization reference sources whose signal quality meets the predefined condition from the synchronization reference sources of the M2 GNSSs, and then Then find the synchronous reference source with the smallest number of hops from M21 as its own synchronization reference source;
  • the order of the second priority and the third priority may be interchanged. For example, it is also possible to find M21 synchronous reference sources whose hop counts satisfy a predefined condition from the synchronous reference sources of M2 GNSSs, and then find the synchronous reference source with the best signal quality from the M21 synchronous reference sources.
  • the signal quality is the first priority
  • the type is the second priority
  • the hop count is the third priority
  • the UE simultaneously receives synchronization reference sources forwarded by multiple UEs, which are respectively from M1.
  • Synchronous reference source of the eNB synchronous reference source of M2 GNSS, synchronous reference source of M3 UEs.
  • the signal quality is the first priority, find the M4 signal synchronization sources that meet the predefined conditions from all the synchronous reference sources, and then find the M41 highest priority types from the M4 synchronization reference sources. Synchronous reference source, and finally find the M411 Sync reference source with the smallest hop count from M41 synchronous reference sources.
  • the order of the second priority and the third priority can be interchanged.
  • the UE simultaneously receives synchronization reference sources forwarded by multiple UEs, which are respectively from the synchronization reference source of the M1 eNBs, the synchronization reference source of the M2 GNSSs, and the synchronization reference source of the M3 UEs.
  • the M4 radiant reference source with the smallest hop count from all the synchronous reference sources find the M41 highest priority among the M4 synchronous reference sources.
  • the synchronous reference source of the type finds the M411 synchronization reference sources whose signal quality meets the predefined conditions from the M41 synchronous reference sources.
  • the order of the second priority and the third priority can be interchanged.
  • Scenario 2 The eNB is a preferred synchronization source. Applicable to scenarios within the network, and/or with eNBs outside the network.
  • Step 1 If the acquired synchronization information indicates that the GNSS or eNB is selected as a synchronization reference source according to a predefined condition.
  • Step 2 The UE selects a synchronization source according to the following criteria according to other synchronization sources (eNB and/or GNSS) detected by it, and synchronization source/synchronization reference source type, signal quality, hop count, and the like forwarded by other UEs (
  • the synchronization source/synchronization reference source at this time may include one of an eNB, a GNSS, and a UE):
  • the synchronization source type is the first priority, and the second priority may be any one of signal quality and hop count;
  • the signal quality is the first priority, and the second priority may be any one of the synchronization source type and the hop count;
  • the hop count is the first priority, and the second priority may be any one of the signal quality and the synchronization source type.
  • the UE may preferentially select the GNSS or the eNB as a synchronization reference source. If the UE detects other synchronization reference sources (eNB and/or GNSS) in addition to synchronization signals and/or control information transmitted by other synchronization source UEs, the UE preferentially from other synchronization reference sources (eNB and/or GNSS) Determine your own sync reference source.
  • eNB and/or GNSS synchronization reference sources
  • the priority information of the synchronization source is not limited to the content described above.
  • the priority information of the synchronization source may further include the priority information of the detection/search duration of the synchronization source, and the priority of the stability of the synchronization source. Information, etc.
  • the first synchronization signal comprises a second synchronization signal and/or a third synchronization signal.
  • step 330 includes:
  • the UE determines the synchronization reference source based on the synchronization information and the type of the at least one synchronization source.
  • the first synchronization signal may include a second synchronization signal and/or a third synchronization signal. That is, both the second synchronization signal and the third synchronization signal may appear simultaneously, or only one of them may appear.
  • the second synchronization signal is generated by a ZC (Zadoff-Chu) sequence
  • the third synchronization signal is generated by two m sequences similar to those in a Long Term Evolution (LTE) system.
  • LTE Long Term Evolution
  • the second synchronization signal may be a Primary D2D Synchronization Signal (PD2DSS) in a Device to Device (D2D) system, or a Primary Synchronization Signal in LTE.
  • P2DSS Primary D2D Synchronization Signal
  • D2D Device to Device
  • LTE Primary Synchronization Signal
  • PSS may also be a signal generated by other lengths of ZC sequences.
  • the third synchronization signal may be a D2D Synchronization Signal (SD2DSS) in D2D, or may be a Secondary Synchronization Signal (SSS) in LTE, and may be generated by other lengths of m-sequences. the sequence of.
  • the modulation method used for the second synchronization signal and the third synchronization signal may be Orthogonal Frequency Division Multiplexing (OFDM) or single carrier frequency division multiple access (Single-carrier Frequency-Division). Multiple Access (SC-FDMA) is not limited in this embodiment of the present invention. Different root sequence numbers can be used to represent different first synchronization sequences, such as the first synchronization sequence 26, 37, and the like.
  • the terminology of the synchronization signal in the D2D system is used, but In the above, the method of the present invention is not limited to the D2D system.
  • the type of the synchronization source is indicated by a combination of different sequences of the second synchronization signals or sequences of the third synchronization signals, so as to be used by the transmitter of the synchronization source and the receiver of the synchronization source.
  • the UE may determine the type of the at least one synchronization source according to the sequence of the second synchronization signal in the first synchronization signal.
  • the first sequence, the second sequence, and the third sequence of the second synchronization signal are respectively used to indicate different synchronization source types, and the first sequence, the second sequence, and the third sequence are different from each other. .
  • the first sequence is used to indicate that the type of the synchronization source is GNSS
  • the second sequence is used to indicate that the type of the synchronization source is a base station
  • the third sequence is used to indicate that the type of the synchronization source is a UE.
  • the PD2DSS has two sequences, which are generated by the ZC sequence, and the corresponding root sequence numbers are 26 and 37, respectively, which are corresponding synchronization sources from the eNB (the scene with the network) and the synchronization.
  • the source comes from the UE (a scenario without a network).
  • the ID numbers of the corresponding synchronization sources are:
  • the PD2DSS sequence 26 the corresponding identifier is id_net, and the set of sequence identifiers is ⁇ 0, 167 ⁇ ;
  • the PD2DSS sequence 37 has a corresponding identifier of id_oon, and the set of sequence identifiers is ⁇ 168, 335 ⁇ .
  • the first sequence is x
  • the second sequence is sequence 26
  • the third sequence is sequence 37.
  • x is the value of the root sequence of the ZC sequence of length 63 corresponding to PD2DSS, which ranges from 1 to 62, and has a lower cross-correlation value from sequences 26 and 37 and from sequences 26 and 37. .
  • the sequence x can be: sequence 29, 31, 23, 25, 34, 32, 40, 38, etc., corresponding to the type of the synchronous reference source being GNSS.
  • the root sequence number of the sequence x used to generate the PD2DSS may be another group, for example, ⁇ 25, 29, 34 ⁇ , which is not limited in the present invention. Its corresponding synchronization source ID number is:
  • the PD2DSS sequence x, the corresponding identifier is id_gnss, and the sequence identifier set is ⁇ 336, 504 ⁇ .
  • the PD2DSS sequence x indicates that the synchronization source type is GNSS, meaning that for the transmitter of the synchronization source, if the synchronization reference source it selects is GNSS, then the PD2DSS signal is transmitted as the sequence x, and the sequence identifier of the corresponding synchronization source is The collection is ⁇ 336,504 ⁇ . For the receiver, if it detects that the PD2DSS sequence sent by the synchronization source is any of 26, 37, x, the corresponding interpretation is to receive the corresponding synchronization source.
  • the types of synchronization sources corresponding to the PD2DSS sequences 26, 37, x are not limited in the embodiment of the present invention.
  • the PD2DSS sequence 26 may also be used to indicate that the type of the synchronization source is the UE
  • the PD2DSS sequence 37 may also be used to indicate that the type of the synchronization source is GNSS
  • the PD2DSS sequence x may also be used to indicate that the type of the synchronization source is the eNB.
  • the second synchronization signal includes a first symbol and a second symbol, and multiple combinations of the sequence used by the first symbol and the sequence used by the second symbol are used to indicate different synchronization source types.
  • FIG. 5 is a schematic diagram of a synchronization signal and a PSBCH channel in D2D communication.
  • the D2D synchronization signal D2DSS is composed of two parts, PD2DSS and SD2DSS.
  • the white line with the horizontal line is the symbol for placing the PSBCH, and the other two demodulation reference signals (DMRS) are used for
  • DMRS demodulation reference signals
  • the PSBCH is used as a reference signal for demodulation, and the last symbol is a symbol that is vacant and is not sent, and is represented by GAP.
  • the PD2DSS occupies symbol 1 and symbol 2 for transmission.
  • the various combinations of the sequence used by symbol 1 and the sequence used by symbol 2 can be used to indicate different types of synchronization sources. E.g:
  • the above ⁇ 26, 37 ⁇ id_gnss: ⁇ 168,335 ⁇ may further indicate that the synchronization reference used as the network is GNSS, in addition to indicating that the synchronization source is a GNSS.
  • ⁇ 37,37 ⁇ id_gnss: ⁇ 505,772 ⁇ In addition to indicating that the used synchronization reference source is GNSS, it can further indicate that the synchronization reference source used when there is no network is GNSS.
  • the number of sequences to be detected by the D2DSS is not increased, but the characteristics of the two symbols are occupied by the PD2DSS, and different combined mappings are respectively used to indicate different types of synchronous reference sources.
  • the UE may further determine a type of the at least one synchronization source according to the sequence of the third synchronization signal.
  • the sequence set of the third synchronization signal includes at least two sequence subsets, and at least two sequence subsets are used to indicate different synchronization source types.
  • the sequence of the second synchronization signal may be the same as the prior art, and the set of the sequence of the third synchronization signal is divided into at least two subsets for indicating different synchronization source types.
  • the set of the sequence of the third synchronization signal is divided into at least two subsets for indicating different synchronization source types.
  • the PD2DSS sequence 26 the first subset of the SD2DSS corresponding sequence indicates that the type of the synchronization source is eNB, and the second subset of the SD2DSS corresponding sequence indicates that the type of the synchronization reference source is GNSS; and/or
  • the PD2DSS sequence 37 the first subset of the SD2DSS corresponding sequence indicates that the type of the synchronization source is the synchronization source is the UE, and the second subset of the SD2DSS corresponding sequence indicates that the type of the synchronization source is GNSS.
  • the set of sequences of SD2DSS can be divided into two subsets using Method 1 and Method 2 described below.
  • the existing ⁇ 0, 167 ⁇ slave synchronization sequence is divided into two subsets, and the two subsets can consecutively take the sequence of the SD2DSS number, such as ⁇ 0, x ⁇ as the first subset, ⁇ x+1, 167 ⁇ is the second subset. It can also be taken at intervals. This embodiment of the present invention does not limit this.
  • the configuration information of the two subsets may be indicated by the base station or may be predefined. E.g:
  • the PD2DSS sequence 26 the synchronization reference source is the eNB corresponding identifier id_net, the SD2DSS sequence set is ⁇ 0, x ⁇ , the synchronization reference source is GNSS corresponding identifier id_gnss, and the SD2DSS sequence set is ⁇ x+1, 167 ⁇ ; and / or,
  • the PD2DSS sequence 37, the synchronization reference source is that the identifier corresponding to the UE is id_oon, the set of SD2DSS sequences is ⁇ 168, y ⁇ , the identifier of the synchronization reference source is GNSS corresponding to id_gnss, and the set of SD2DSS sequences is ⁇ y+1, 335 ⁇ .
  • mapping methods for the identification set of the synchronization source which are not enumerated here, as long as the GNSS corresponds to a subset of the set of SD2DSS sequences.
  • the detection complexity of the receiver is not increased.
  • Method 2 The existing SD2DSS sequence ⁇ 0, 167 ⁇ is unchanged, and the number of SD2DSS sequences is extended, for example, the extended SD2DSS sequence is ⁇ 0, 335 ⁇ .
  • a synchronization sequence that indicates the new synchronization source type E.g:
  • the PD2DSS sequence 26 the synchronization reference source is the eNB corresponding identifier id_net, the SD2DSS sequence set is ⁇ 0, 167 ⁇ , the synchronization reference source is GNSS corresponding identifier id_gnss, and the SD2DSS sequence set is ⁇ 167, 335 ⁇ ; and/or
  • the PD2DSS sequence 37 the synchronization reference source is the identifier corresponding to the UE is id_oon, the set of SD2DSS sequences is ⁇ 336, 503 ⁇ , the identifier of the synchronization reference source is GNSS corresponding to id_gnss, and the set of SD2DSS sequences is ⁇ 504, 771 ⁇ .
  • the information of the extended SD2DSS sequence set may be a base station configuration or may be predefined.
  • the PD2DSS sequence is not newly added, and the available sequence of the SD2DSS is extended to indicate different synchronization source types, thereby providing a number of synchronization sources that can be identified.
  • the third synchronization signal includes a third symbol and a fourth symbol, and the combination of the sequence used by the third symbol and the sequence used by the fourth symbol is used to indicate different synchronization of the synchronization source. Source type.
  • SD2DSS occupies symbol 1 and symbol 2 for transmission.
  • the various combinations of the sequence used by symbol 1 and the sequence used by symbol 2 can be used to indicate different types of synchronization sources. E.g:
  • x and y are any sequence of the SD2DSS sequence in the set ⁇ 0, 167 ⁇ , or any sequence in the ⁇ 0, 335 ⁇ set, and the numbers of the SD2DSS sequences corresponding to x and y are different.
  • the number of sequences to be detected by the synchronization signal is not increased, but the characteristics of the two symbols occupied by the third synchronization signal are utilized, and different combination mappings are respectively performed to indicate different types of synchronization reference sources.
  • the UE may also determine the type of the synchronization source according to a combination of the sequence of the second synchronization signal and the sequence of the third synchronization signal.
  • a plurality of combinations of a sequence used by the first symbol, a sequence used by the second symbol, a sequence used by the third symbol, and a sequence used by the fourth symbol are used to indicate different synchronization source types;
  • the different combinations of the sequences used by the two symbols occupied by the second synchronization signal and the sequences used by the third synchronization signal are used to indicate different synchronization source types.
  • the method 300 further includes: the UE receiving the first control information sent by the at least one synchronization source.
  • the UE receives first control information transmitted by each of the at least one synchronization source.
  • the control information may include at least one of the following information: type auxiliary indication information of the synchronization source, indication information indicating whether the synchronization signal is valid, indication information of whether the synchronization signal is transmitted, indication information of a transmission period of the synchronization signal, and synchronization signal transmission.
  • the indication information of the time-frequency position and the indication information of the hop count of the synchronization source may include at least one of the following information: type auxiliary indication information of the synchronization source, indication information indicating whether the synchronization signal is valid, indication information of whether the synchronization signal is transmitted, indication information of a transmission period of the synchronization signal, and synchronization signal transmission.
  • the control information When the control information is transmitted from the UE, the control information may be carried in multiple manners, for example, may be explicitly displayed through a control channel such as a display field in a Physical Sidelink Broadcast Channel (PSBCH). Implicitly indicating, or by using a Demodulation Reference Signal (DMRS) in the PSBCH channel to carry the indication, and also using a Cyclic Redundancy Check (CRC) mask of the PSBCH packet. Implicit indication. For example, it may also be indicated by a control channel of service data sent by the UE, such as a physical side link control channel (PSCCH) channel. It may also be indicated by a traffic channel transmitted by the UE, such as a Physical Sidelink Shared Channel (PSSCH). The invention is not limited thereto.
  • DMRS Demodulation Reference Signal
  • CRC Cyclic Redundancy Check
  • the indication information of the hop count of the synchronization source is used to indicate the current hop count of the synchronization source of the UE type synchronization source to its forwarding.
  • the UE when the UE can detect a valid GNSS, and/or receive signaling sent by the eNB, indicating that the UE uses the GNSS as a synchronization reference source or as a preferred synchronization reference source, the UE uses the GNSS as a synchronization reference source, and synchronizes to the GNSS. on.
  • the UE can directly receive the control information without receiving the D2DSS signal; if the receiver has been synchronized to the synchronization source with the GNSS as the synchronization reference source, the receiver only needs to detect a small amount. D2DSS, then receive the control information directly.
  • the UE can transmit control information as a synchronization source while transmitting the synchronization signal or not transmitting the synchronization signal in a more sparse manner.
  • the synchronizing signal is sent in a more sparse manner, including: transmitting a synchronization signal only in a partial subframe starting in a synchronization signal subframe, and not transmitting a synchronization signal in a subsequent subframe; or being larger than a PSBCH period (eg, 40 ms)
  • the period such as 80ms, 120ms, 160ms, etc., sends the synchronization signal; or directly does not send the synchronization signal, only the control information is sent.
  • the UE when the UE detects the GNSS, the UE uses the GNSS as the synchronization reference source, and the UE may not send the synchronization signal or send the synchronization signal less, which can reduce unnecessary signal transmission and reduce other UEs. Unnecessary detection of the synchronization signal reduces power consumption and reduces the complexity of the UE.
  • step 330 may include:
  • the UE determines the synchronization reference source according to the synchronization information, the first synchronization signal, and the type of the at least one synchronization source.
  • the UE may further determine a type of the at least one synchronization source according to the sequence of the second synchronization signal and/or the sequence of the third synchronization signal and the first control information.
  • control information may be 1-bit indication information, which is represented by Flag:
  • control information may be carried in a display field in the PSBCH channel, or may be implicitly indicated by other fields in the PSBCH channel or DMRS or CRC on the PSBCH channel. This embodiment of the present invention does not limit this.
  • the method for transmitting the D2DSS sequence and the signal is not required to be modified, and the type of the synchronization source is indicated by the joint control information.
  • UE7 in FIG. 2B is a relatively isolated UE. If it can receive the synchronization information sent by UE4, or can detect GNSS subsequently, it can synchronize to UE4 or GNSS.
  • the method 300 may further include: the UE sends the second synchronization signal and/or the second control information according to the synchronization reference source, where the second synchronization signal and/or the second control information is used to indicate the synchronization reference.
  • the type of source may be used to indicate the synchronization reference.
  • the UE itself can transmit the synchronization signal and/or control information as a synchronization source.
  • the specific manner of the second synchronization signal and/or the second control information indicating the type of the synchronization reference source may refer to the previous first synchronization signal and/or the first control information indicating the method of synchronizing the reference source, in order to avoid repetition, here No longer.
  • the UE detects that the synchronization source satisfies at least one of the following:
  • the signal quality of other synchronization sources detected by the UE does not meet the predefined threshold value
  • the signal quality of other synchronization sources detected by the UE has a synchronization source that satisfies a predefined threshold, but the number of hops from other synchronization sources is greater than a predefined threshold.
  • the UE itself becomes a synchronization source and sends synchronization signals and/or control information.
  • the synchronization information may further include at least one of the following: configuration information of a synchronization sequence used by the synchronization signal; transmission frequency domain location information of the synchronization signal and/or control information; transmission time domain location information of the synchronization signal and/or control information; synchronization Transmit power information of the signal and/or control information.
  • the UE transmits a synchronization signal and/or control information according to the synchronization information.
  • the method 300 may further include:
  • the UE determines a timing offset between a timing reference of the synchronization reference source and a timing reference of the synchronization reference source of the other link;
  • the UE communicates based on the timing reference and timing offset of the synchronous reference source.
  • the device-to-device timing and synchronization reference can be unified with GNSS, and UTC time is unified. Time base. Between eNBs, especially asynchronous eNBs, the timing reference must be different from the device-to-device timing reference.
  • the immediate problem is that, as shown in FIG. 7, the time start position of the system frame number between the cellular links is different from the start position of the time of the system frame number of the device-to-device link. This difference will cause inconsistencies in the understanding of the scheduling signaling between the base station and the device-to-device link. As shown in FIG. 7, since the timing between the cellular link and the device-to-device link is completely asynchronous, the correspondence between the device-to-device transmission parameters configured by the base station may not be unique.
  • the UE can perform communication by determining a timing deviation between a timing reference of a synchronous reference source and a timing reference of a synchronous reference source of another link, and according to a timing reference and a timing deviation of the synchronous reference source.
  • the timing reference between the two links is different.
  • the UE may determine a timing offset between the timing reference of the synchronization reference source and the timing reference of the synchronization reference source of the other link according to the indication of the base station.
  • the UE determines a timing offset between a timing reference of the synchronization reference source and a timing reference of the synchronization reference source of the other link, including:
  • timing deviation indication information sent by the base station, where the timing deviation indication information is used to indicate a timing offset
  • the UE determines the timing offset based on the timing deviation indication information.
  • the timing deviation indication information may include a deviation value between a timing reference of the synchronization reference source and a timing reference of the synchronization reference source of another link;
  • the indication information includes:
  • the predefined fixed time reference may be UTC timing or UTC timing based Pre-defined device-to-device system frame number start position or the start position of the maximum spectable frame.
  • the length of the system frame and the maximum spectable frame are all predefined. For example, in LTE, the length of the system frame number is 10 ms, and the length of the maximum spectable frame is 1024 radio frames, that is, 10.24 s.
  • the start time of the radio frame number of the device-to-device link needs to be predefined at UTC time.
  • the start time of the radio frame 0 on the device-to-device link is:
  • T start Mod (t UTC + t 1, N),
  • T start is the start time of the radio frame 0 on the device-to-device link;
  • t UTC is the current UTC time;
  • t 1 is a deviation value.
  • N is a predefined constant. When N is 1024, the unit of all time is 10ms, and when N is 10240, all time units are 1ms. Mod is the remainder operator.
  • the signaling and/or configuration information sent by the base station to the device is configured based on the time T eNB of the frame number of the start time of its system frame number.
  • the base station can configure the timing offset value (offset) between the two links to the UE according to its own timing.
  • the device-to-device link transmission information configured by the base station can be mapped to its own transceiver parameters. For example, if the offset value is 100 ms, the configuration information indicating that the D2D link is received by the eNB is: sending device-to-device data on the subframe 3, and the time that the UE corresponds to its link is in the device-to-device chain.
  • the device-to-device data is transmitted on the subframe 103 on the road.
  • the UE may also determine a timing offset between the timing reference of the synchronization reference source and the timing reference of the synchronization reference source of the other link according to a predefined rule.
  • the UE determines a timing offset between a timing reference of the synchronization reference source and a timing reference of the synchronization reference source of the other link, including:
  • the UE acquires a timing reference of a synchronization reference source of another link
  • the UE determines the timing offset based on the timing reference of the synchronization reference source and the timing reference of the synchronization reference source of the other link.
  • the UE acquires a list of timings of neighboring cells through a synchronization process to the base station, and then if the UE synchronizes to the GNSS, the timing of the detected neighboring cells is based on a predefined GNSS-based timing reference.
  • the timing offset value used by each cell UE is calculated.
  • the start time T start of the radio frame 0 on the device-to-device link needs to be predefined.
  • a determination rule for the deviation between T start and T eNB is also defined.
  • the value of offset is determined according to the following rules:
  • Offset Mod(T start –T eNB ,N), N is a predefined constant. When N is 1024, the unit of all time is 10ms. When N is 10240, all time units are 1ms. Mod is the remainder operator.
  • the UE can determine the timing offset between the two links according to the two methods described above, thereby obtaining signaling of its transmit and receive parameters.
  • FIG. 8 is a schematic flow diagram of a synchronization method 800 in accordance with an embodiment of the present invention.
  • Method 800 corresponds to method 300, and the corresponding content will be omitted as appropriate herein. As shown in FIG. 8, method 800 includes the following.
  • the base station determines synchronization information, where the synchronization information includes at least one of the following: the selection parameter information of the synchronization source, the indication information of the synchronization source, and the priority information of the synchronization source.
  • the base station sends synchronization information to the UE.
  • the UE may determine the synchronization reference source according to the synchronization information.
  • the user equipment by sending synchronization information to the user equipment, the user equipment can determine the synchronization reference source according to the synchronization information, thereby enabling synchronization and ensuring optimal communication performance.
  • the synchronization method 800 further includes:
  • the base station sends control information to the user equipment, the control information being used to determine the type and/or identity of the synchronization reference source.
  • the synchronization method 800 further includes: the base station sends control information to the user equipment, where the control information includes at least one of the following information: type indication indication information of the synchronization source, and an indication of a transmission period of the synchronization signal.
  • the indication information of the hop count of the synchronization source is used to indicate the maximum hop count of the synchronization source.
  • the UE may forward the synchronization source within the maximum number of hops.
  • step 810 specifically includes:
  • the base station determines synchronization information based on information of at least one synchronization source.
  • the synchronization method 800 further includes:
  • the base station sends timing deviation indication information to the user equipment, and the timing deviation indication information is used to indicate a timing offset between the timing reference of the synchronization reference source of the user equipment and the timing reference of the synchronization reference source of the other link.
  • the user equipment by sending synchronization information to the user equipment, the user equipment can determine the synchronization reference source according to the synchronization information, thereby enabling synchronization and ensuring optimal communication performance.
  • FIG. 9 is a schematic flow chart of a synchronization method 900 in accordance with another embodiment of the present invention.
  • Method 900 corresponds to method 300, and the corresponding content will be omitted as appropriate herein.
  • method 900 includes the following.
  • the UE determines a synchronization reference source, and the type of the synchronization reference source is any one of a GNSS, a base station, and a UE.
  • the synchronization reference source may be a GNSS, a base station or other UE, and may also be the UE itself.
  • the UE sends a synchronization signal according to the synchronization reference source, where the synchronization signal includes a first synchronization signal and/or a second synchronization signal, and the sequence of the first synchronization signal and/or the sequence of the second synchronization signal is used to indicate the type of the synchronization reference source.
  • the UE can serve as a synchronization source.
  • the synchronization signal sent by the user equipment can indicate the type of the synchronization reference source, so that other user equipment can be synchronized according to the synchronization.
  • the signal determines the synchronization reference source so that synchronization can be achieved, ensuring optimal communication performance.
  • sequence of the first synchronization signal and/or the sequence of the second synchronization signal is used to indicate the type of the synchronization reference source includes:
  • At least one sequence of the first synchronization signal is used to indicate the type of the synchronization reference source
  • the first synchronization signal occupies the first symbol and the second symbol, and at least one combination of the sequence used by the first symbol and the sequence used by the second symbol is used to indicate the type of the synchronization reference source; or
  • the sequence set of the second synchronization signal includes at least two sequence subsets, and at least one subset of the at least two sequence subsets is used to indicate a type of the synchronization reference source; or
  • the second synchronization signal includes a third symbol and a fourth symbol, and at least one combination of the sequence used by the third symbol and the sequence used by the fourth symbol is used to indicate the type of the synchronization reference source; or
  • the first synchronization signal occupies the first symbol and the second symbol
  • the second synchronization signal occupies the third symbol and the fourth symbol
  • the sequence used by the first symbol the sequence used by the second symbol
  • the sequence used by the third symbol the fourth symbol
  • At least one combination of the sequences used is used to indicate the type of synchronization reference source.
  • the method 900 further includes:
  • the user equipment sends control information, where the control information includes at least one of the following information: The type auxiliary indication information of the step source, the indication information of the transmission period of the synchronization signal, the indication information of whether the synchronization signal is valid, the indication information of whether the synchronization signal is transmitted, the indication information of the time-frequency position of the synchronization signal transmission, and the hop count of the synchronization source Instructions.
  • the indication information of the hop count of the synchronization source is used to indicate the current hop count of the user equipment to the synchronization reference source.
  • sequence of first synchronization signals and/or the sequence of second synchronization signals, and control information are used to indicate the type of synchronization reference source.
  • the method for determining the synchronization reference source by the UE in step 910 may refer to the method for determining the synchronization reference source by the UE in the method 300. To avoid repetition, details are not described herein again.
  • the synchronization signal sent by the user equipment can indicate the type of the synchronization reference source, so that other user equipment can be synchronized according to the synchronization.
  • the signal determines the synchronization reference source so that synchronization can be achieved, ensuring optimal communication performance.
  • a user equipment and a base station according to an embodiment of the present invention are described in detail below with reference to FIGS. 10 through 15.
  • FIG. 10 is a schematic block diagram of a user equipment 1000 in accordance with an embodiment of the present invention.
  • the user equipment 1000 includes an obtaining unit 1010, a transceiver unit 1020, and a determining unit 1030.
  • the obtaining unit 1010 is configured to acquire synchronization information, where the synchronization information includes at least one of the following: the selection parameter information of the synchronization source, the indication information of the synchronization source, and the priority information of the synchronization source;
  • the transceiver unit 1020 is configured to receive a first synchronization signal sent by at least one synchronization source;
  • the determining unit 1030 is configured to determine a synchronization reference source according to the synchronization information acquired by the obtaining unit 1010 and the first synchronization signal received by the transceiver unit 1020.
  • the synchronization reference source is determined according to the synchronization information and the synchronization signal sent by the at least one synchronization source, and synchronization can be implemented.
  • the determining unit 1030 is specifically configured to select, according to the first synchronization signal, a synchronization source that satisfies the selection parameter of the at least one synchronization source as the synchronization reference source.
  • the indication information of the synchronization source is used to indicate the first synchronization source
  • the determining unit 1030 is specifically configured to select the first synchronization source as the synchronization reference source according to the first synchronization signal.
  • the determining unit 1030 is specifically configured to: the user equipment select, according to the priority information and the first synchronization signal, a synchronization source with the highest priority among the at least one synchronization source as the synchronization reference source.
  • the indication information of the synchronization source is used to indicate the first synchronization source, and the determining unit 1030 is specifically configured to:
  • the first synchronization source satisfies a predefined condition, selecting the first synchronization source as the synchronization reference source;
  • the second synchronization source having the highest priority among the at least one synchronization source except the first synchronization source is selected as the synchronization reference source according to the priority information.
  • the first synchronization signal includes a second synchronization signal and/or a third synchronization signal
  • the determining unit 1030 is specifically configured to:
  • the synchronization reference source is determined based on the synchronization information and the type of the at least one synchronization source.
  • the first sequence, the second sequence, and the third sequence of the second synchronization signal are respectively used to indicate different synchronization source types, and the first sequence, the second sequence, and the third sequence are different from each other; or
  • the second synchronization signal occupies the first symbol and the second symbol, and the plurality of combinations of the sequence used by the first symbol and the sequence used by the second symbol are used to indicate different synchronization source types; or
  • the sequence set of the third synchronization signal includes a plurality of sequence subsets, and the plurality of sequence subsets are used to indicate different synchronization source types; or
  • the third synchronization signal occupies the third symbol and the fourth symbol, and the plurality of combinations of the sequence used by the third symbol and the sequence used by the fourth symbol are used to indicate different synchronization source types; or
  • the second synchronization signal occupies the first symbol and the second symbol
  • the third synchronization signal occupies the third symbol and the fourth symbol
  • the sequence used by the first symbol the sequence used by the second symbol
  • the sequence used by the third symbol Various combinations of sequences used are used to indicate different synchronization source types.
  • the transceiver unit 1020 is further configured to receive the first control information that is sent by the at least one synchronization source.
  • the determining unit 1030 is specifically configured to:
  • the synchronization reference source is determined based on the synchronization information, the first synchronization signal, and the type of the at least one synchronization source.
  • the transceiver unit 1020 is further configured to receive, by the at least one synchronization source, the first control information, where the first control information includes at least one of the following information: a type auxiliary indication information of the synchronization source, and a sending period of the synchronization signal.
  • the indication information, the indication information of whether the synchronization signal is transmitted, the indication information of whether the synchronization signal is valid, the indication information of the time-frequency position of the synchronization signal transmission, and the synchronization source The indication of the hop count.
  • the first synchronization signal includes a second synchronization signal and/or a third synchronization signal
  • the determining unit 1030 is specifically configured to: according to the sequence of the second synchronization signal and/or the sequence of the third synchronization signal, and the first control information Determine the type of at least one synchronization source.
  • the obtaining unit 1010 is specifically configured to receive synchronization information sent by the base station.
  • the transceiver unit 1020 is further configured to: before the acquiring unit 1010 receives the synchronization information, send information of the at least one synchronization source to the base station, so that the base station determines the synchronization information according to the information of the at least one synchronization source.
  • the transceiver unit 1020 is further configured to send a fourth synchronization signal and/or second control information according to the synchronization reference source, where the fourth synchronization signal and/or the second control information is used to indicate a type of the synchronization reference source.
  • the determining unit 1030 is further configured to determine a timing offset between a timing reference of the synchronization reference source and a timing reference of the synchronization reference source of another link; the transceiver unit 1020 is further configured to: according to the timing reference of the synchronization reference source The timing deviation determined by the determining unit 1030 is communicated.
  • the transceiver unit 1020 is further configured to receive the timing deviation indication information sent by the base station, where the timing deviation indication is used to indicate the timing deviation, and the determining unit 1030 is specifically configured to determine the timing according to the timing deviation indication information received by the transceiver unit. deviation.
  • the obtaining unit 1010 is further configured to acquire a timing reference of the synchronization reference source of another link.
  • the determining unit 1020 is specifically configured to: according to the timing reference of the synchronization reference source and the timing reference of the synchronization reference source of another link Determine the timing deviation.
  • user equipment 1000 in accordance with an embodiment of the present invention may correspond to user equipment in synchronization method 300 in accordance with an embodiment of the present invention, and that the above and other operations and/or functions of various units/modules in user equipment 1000 are respectively The corresponding process of the method 300 of FIG. 3 is implemented, and for brevity, no further details are provided herein.
  • the synchronization reference source is determined according to the synchronization information and the synchronization signal sent by the at least one synchronization source, and synchronization can be implemented.
  • FIG. 11 is a schematic block diagram of a base station 1100 according to another embodiment of the present invention. As shown in FIG. 11, the base station 1100 includes a determining unit 1110 and a transmitting unit 1120.
  • the determining unit 1110 is configured to send synchronization information to the user equipment, where the synchronization information includes at least one of the following: the selection parameter information of the synchronization source, the indication information of the synchronization source, and the priority information of the synchronization source, so that the user equipment Synchronization information determines a synchronization reference source;
  • the sending unit 1120 is configured to send synchronization information to the user equipment.
  • the user equipment by sending synchronization information to the user equipment, the user equipment can determine the synchronization reference source according to the synchronization information, thereby enabling synchronization and ensuring optimal communication performance.
  • the sending unit 1120 is further configured to send, to the user equipment, control information, where the control information is used to indicate a type and/or an identifier of the synchronization reference source.
  • the sending unit 1120 is further configured to: send, to the user equipment, control information, where the control information may include at least one of the following information: type indication indication information of the synchronization source, indication information of a transmission period of the synchronization signal, and whether the synchronization signal is The effective indication information, the indication of whether the synchronization signal is transmitted, the indication information of the time-frequency position of the synchronization signal transmission, and the indication information of the hop count of the synchronization source.
  • control information may include at least one of the following information: type indication indication information of the synchronization source, indication information of a transmission period of the synchronization signal, and whether the synchronization signal is The effective indication information, the indication of whether the synchronization signal is transmitted, the indication information of the time-frequency position of the synchronization signal transmission, and the indication information of the hop count of the synchronization source.
  • the base station 1100 may further include: a receiving unit 1130.
  • the receiving unit 1130 is configured to receive, by the sending unit 1120, information about at least one synchronization source that is sent by the user equipment, before sending the synchronization information to the user equipment;
  • the determining unit 1110 is specifically configured to determine synchronization information according to information of at least one synchronization source received by the receiving unit 1130.
  • the sending unit 1120 is further configured to send timing deviation indication information to the user equipment, where the timing deviation indication information is used to indicate a timing reference of the synchronization reference source of the user equipment and a timing reference of the synchronization reference source of another link. Timing deviation.
  • base station 1100 in accordance with an embodiment of the present invention may correspond to a base station in synchronization method 800 in accordance with an embodiment of the present invention, and that the above and other operations and/or functions of various units/modules in base station 1100 are respectively implemented to implement FIG. The corresponding process of the method 800 is not repeated here for brevity.
  • the user equipment by sending synchronization information to the user equipment, the user equipment can determine the synchronization reference source according to the synchronization information, thereby enabling synchronization and ensuring optimal communication performance.
  • FIG. 12 is a schematic block diagram of a user equipment 1200 according to another embodiment of the present invention. As shown in FIG. 12, the user equipment 1200 includes a determining unit 1210 and a transmitting unit 1220.
  • a determining unit 1210 configured to determine a synchronization reference source, where the type of the synchronization reference source is any one of a GNSS, a base station, and a user equipment;
  • the sending unit 1220 is configured to send a synchronization signal according to the synchronization reference source, where the synchronization signal includes a first synchronization signal and/or a second synchronization signal, and the sequence of the first synchronization signal and/or the sequence of the second synchronization signal is used to indicate the synchronization reference source. type.
  • the synchronization signal sent by the user equipment can indicate the type of the synchronization reference source, so that other user equipments can determine the synchronization reference source according to the synchronization signal, thereby enabling synchronization and ensuring optimal communication performance.
  • At least one sequence of the first synchronization signal is used to indicate the type of the synchronization reference source
  • the first synchronization signal occupies the first symbol and the second symbol, and at least one combination of the sequence used by the first symbol and the sequence used by the second symbol is used to indicate the type of the synchronization reference source; or
  • the sequence set of the second synchronization signal includes at least two sequence subsets, and at least one subset of the at least two sequence subsets is used to indicate a type of the synchronization reference source; or
  • the second synchronization signal includes a third symbol and a fourth symbol, and at least one combination of the sequence used by the third symbol and the sequence used by the fourth symbol is used to indicate the type of the synchronization reference source; or
  • the first synchronization signal occupies the first symbol and the second symbol
  • the second synchronization signal occupies the third symbol and the fourth symbol
  • the sequence used by the first symbol the sequence used by the second symbol
  • the sequence used by the third symbol the fourth symbol
  • At least one combination of the sequences used is used to indicate the type of synchronization reference source.
  • the sending unit 1220 is further configured to send control information, a sequence of the first synchronization signal and/or a sequence of the second synchronization signal, and control information to indicate a type of the synchronization reference source.
  • the sending unit 1220 is further configured to: send control information, where the control information includes at least one of the following information: type auxiliary indication information of the synchronization source, indication information of a transmission period of the synchronization signal, and indication information of whether the synchronization signal is valid. And indication information of whether the synchronization signal is transmitted, indication information of the time-frequency position of the synchronization signal transmission, and indication information of the hop count of the synchronization source.
  • user equipment 1200 in accordance with an embodiment of the present invention may correspond to user equipment in synchronization method 900 in accordance with an embodiment of the present invention, and that the above and other operations and/or functions of various units/modules in user equipment 1200 are respectively
  • the corresponding process of the method 900 of FIG. 9 is implemented, and for brevity, no further details are provided herein.
  • the synchronization signal sent by the user equipment can indicate the type of the synchronization reference source, so that other user equipment can be synchronized according to the synchronization.
  • the signal determines the type of the synchronous reference source so that synchronization can be achieved, ensuring optimal communication performance.
  • FIG. 13 is a schematic block diagram of a user equipment 1300 according to another embodiment of the present invention.
  • user equipment 1300 includes a processor 1310, a memory 1320, a bus system 1330, and a transceiver 1340.
  • the processor 1310, the memory 1320, and the transceiver 1340 are connected by a bus system 1330 for storing instructions, and the processor 1310 is configured to execute the memory. 1320 stored instructions.
  • the processor 1310 is configured to acquire synchronization information, where the synchronization information includes at least one of the following: the selection parameter information of the synchronization source, the indication information of the synchronization source, and the priority information of the synchronization source;
  • the transceiver 1340 is configured to receive a first synchronization signal sent by at least one synchronization source;
  • the processor 1310 is further configured to determine a synchronization reference source according to the synchronization information and the first synchronization signal.
  • the synchronization reference source is determined according to the synchronization information and the synchronization signal sent by the at least one synchronization source, and synchronization can be implemented.
  • the processor 1310 may be a central processing unit (CPU), and the processor 1310 may also be other general-purpose processors, digital signal processing (Digital Signal Processing, referred to as DSP), Application Specific Integrated Circuit (ASIC), Field-Programmable Gate Array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, and the like.
  • DSP Digital Signal Processing
  • ASIC Application Specific Integrated Circuit
  • FPGA Field-Programmable Gate Array
  • the general purpose processor may be a microprocessor or the processor or any conventional processor or the like.
  • the memory 1320 can include read only memory and random access memory and provides instructions and data to the processor 1310. A portion of the memory 1320 may also include a non-volatile random access memory. For example, the memory 1320 can also store information of the device type.
  • the bus system 1330 may include a power bus, a control bus, a status signal bus, and the like in addition to the data bus. However, for clarity of description, various buses are labeled as bus system 1330 in the figure.
  • each step of the above method may be completed by an integrated logic circuit of hardware in the processor 1310 or an instruction in a form of software.
  • the steps of the method disclosed in the embodiments of the present invention may be directly implemented as a hardware processor, or may be performed by a combination of hardware and software modules in the processor.
  • the software modules can be located in a conventional storage medium such as random access memory, flash memory, read only memory, programmable read only memory, or electrically erasable programmable memory, registers, and the like.
  • the storage medium is located in the memory 1320, and the processor 1310 reads the information in the memory 1320 and performs the steps of the above method in combination with its hardware. To avoid repetition, it will not be described in detail here.
  • the transceiver 1340 is further configured to receive synchronization information sent by the base station. Accordingly, the processor 1310 acquires synchronization information from the transceiver 1340.
  • the processor 1310 is specifically configured to select, according to the first synchronization signal, a synchronization source that satisfies the selection parameter of the at least one synchronization source as the synchronization reference source.
  • the indication information of the synchronization source is used to indicate the first synchronization source, and the processor 1310 is specifically configured to select the first synchronization source as the synchronization reference source according to the first synchronization signal.
  • the processor 1310 is specifically configured to: the user equipment select, according to the priority information and the first synchronization signal, a synchronization source with the highest priority among the at least one synchronization source as a synchronization reference source.
  • the indication information of the synchronization source is used to indicate the first synchronization source.
  • processor 1310 is specifically configured to:
  • the first synchronization source satisfies a predefined condition, selecting the first synchronization source as the synchronization reference source;
  • the second synchronization source having the highest priority among the at least one synchronization source except the first synchronization source is selected as the synchronization reference source according to the priority information.
  • the first synchronization signal includes a second synchronization signal and/or a third synchronization signal
  • the processor 1310 is specifically configured to:
  • the synchronization reference source is selected based on the synchronization information and the type of at least one synchronization source.
  • the first sequence, the second sequence, and the third sequence of the second synchronization signal are respectively used to indicate different synchronization source types, and the first sequence, the second sequence, and the third sequence are different from each other; or
  • the second synchronization signal occupies the first symbol and the second symbol, and the plurality of combinations of the sequence used by the first symbol and the sequence used by the second symbol are used to indicate different synchronization source types; or
  • the sequence set of the third synchronization signal includes a plurality of sequence subsets, and the plurality of sequence subsets are used to indicate different synchronization source types; or
  • the third synchronization signal occupies the third symbol and the fourth symbol, and the plurality of combinations of the sequence used by the third symbol and the sequence used by the fourth symbol are used to indicate different synchronization source types; or
  • the second synchronization signal occupies the first symbol and the second symbol
  • the third synchronization signal occupies the third symbol and the fourth symbol
  • the sequence used by the first symbol the sequence used by the second symbol
  • the sequence used by the third symbol Various combinations of sequences used are used to indicate different synchronization source types.
  • the transceiver 1340 is further configured to receive the first control information that is sent by the at least one synchronization source.
  • processor 1310 is specifically configured to:
  • the transceiver 1340 is further configured to receive, by the at least one synchronization source, the first control information, where the first control information includes at least one of the following information: a type of the auxiliary information of the synchronization source, and a sending period of the synchronization signal.
  • the first synchronization signal includes a second synchronization signal and/or a third synchronization signal
  • the processor 1310 is specifically configured to: according to the sequence of the second synchronization signal and/or the sequence of the third synchronization signal, and the first control information Determine the type of at least one synchronization source.
  • the transceiver 1340 is further configured to: before receiving the synchronization information, send information of the at least one synchronization source to the base station, so that the base station determines the synchronization information according to the information of the at least one synchronization source.
  • the transceiver 1340 is further configured to send a fourth synchronization signal and/or second control information according to the synchronization reference source, where the fourth synchronization signal and/or the second control information is used to indicate a type of the synchronization reference source.
  • the processor 1310 is further configured to determine a timing offset between a timing reference of the synchronization reference source and a timing reference of the synchronization reference source of the other link; the transceiver 1340 is further configured to: according to the timing reference of the synchronization reference source The timing offset determined by the processor 1310 is communicated.
  • the transceiver 1340 is further configured to: receive timing deviation indication information sent by the base station, where the timing deviation indication is used to indicate the timing deviation, and the processor 1310 is specifically configured to determine, according to the timing deviation indication information received by the transceiver 1340. Timing deviation.
  • the processor 1310 is further configured to acquire a timing reference of a synchronization reference source of another link.
  • the processor 1310 is specifically configured to determine, according to a timing reference of the synchronization reference source and a timing reference of the synchronization reference source of another link. Timing deviation.
  • the user equipment 1300 according to the embodiment of the present invention may correspond to the user equipment in the synchronization method 300 according to the embodiment of the present invention and the user equipment 1000 according to the embodiment of the present invention, and the respective units/modules in the user equipment 1300
  • the foregoing and other operations and/or functions are respectively implemented to implement the corresponding processes of the method 300 of FIG. 3, and are not described herein again for brevity.
  • the synchronization reference source is determined according to the synchronization information and the synchronization signal of the at least one synchronization source, and synchronization can be implemented.
  • FIG. 14 is a schematic block diagram of a base station 1400 according to another embodiment of the present invention.
  • base station 1400 includes a processor 1410, a memory 1420, a bus system 1430, and a transceiver 1440.
  • the processor 1410, the memory 1420, and the transceiver 1440 are connected by a bus system 1430 for storing instructions for executing instructions stored by the memory 1420.
  • the processor 1410 is configured to determine synchronization information, where the synchronization information includes at least one of the following: the selection parameter information of the synchronization source, the indication information of the synchronization source, and the priority information of the synchronization source;
  • the transceiver 1440 is configured to send synchronization information to the user equipment.
  • the user equipment by sending synchronization information to the user equipment, the user equipment can determine the synchronization reference source according to the synchronization information, thereby enabling synchronization and ensuring optimal communication performance.
  • the processor 1410 may be a CPU, and the processor 1410 may also be other general-purpose processors, DSPs, ASICs, FPGAs, or other programmable logic devices, discrete gates or transistor logic devices, and discrete Hardware components, etc.
  • the general purpose processor may be a microprocessor or the processor or any conventional processor or the like.
  • the memory 1420 can include read only memory and random access memory and provides instructions and data to the processor 1410. A portion of the memory 1420 can also include a non-volatile random access memory. For example, the memory 1420 can also store information of the device type.
  • the bus system 1430 may include a power bus, a control bus, a status signal bus, and the like in addition to the data bus. However, for clarity of description, various buses are labeled as bus system 1430 in the figure.
  • each step of the above method may be completed by an integrated logic circuit of hardware in the processor 1410 or an instruction in a form of software.
  • the steps of the method disclosed in the embodiments of the present invention may be directly implemented as a hardware processor, or may be performed by a combination of hardware and software modules in the processor.
  • the software modules can be located in a conventional storage medium such as random access memory, flash memory, read only memory, programmable read only memory, or electrically erasable programmable memory, registers, and the like.
  • the storage medium is located in the memory 1420, and the processor 1410 reads the information in the memory 1420 and, in conjunction with its hardware, performs the steps of the above method. To avoid repetition, it will not be described in detail here.
  • the transceiver 1440 is further configured to send control information to the user equipment, where the control information is used to indicate a type and/or an identifier of the synchronization reference source.
  • the transceiver 1440 is further configured to send, to the user equipment, control information, where the control information includes at least one of the following information: type indication indication information of the synchronization source, indication information of a transmission period of the synchronization signal, and whether the synchronization signal is valid.
  • the transceiver 1440 is further configured to: receive information of the at least one synchronization source sent by the user equipment, before sending the synchronization information to the user equipment; the processor 1410, configured to: according to the at least one synchronization source received by the transceiver 1440 The information determines the synchronization information.
  • the transceiver 1440 is further configured to send timing deviation indication information to the user equipment, where the timing deviation indication information is used to indicate a timing reference of the synchronization reference source of the user equipment and a timing reference of the synchronization reference source of another link. Timing deviation.
  • base station 1400 in accordance with an embodiment of the present invention may correspond to base stations in synchronization method 800 in accordance with embodiments of the present invention, as well as base station 1100 in accordance with an embodiment of the present invention, and the above and other operations of various units/modules in base station 1400
  • the functions and/or functions are respectively implemented in order to implement the corresponding processes of the method 800 of FIG. 8.
  • no further details are provided herein.
  • the user equipment by sending synchronization information to the user equipment, the user equipment can determine the synchronization reference source according to the synchronization information, thereby enabling synchronization and ensuring optimal communication performance.
  • FIG. 15 is a schematic block diagram of a user equipment 1500 according to another embodiment of the present invention.
  • user equipment 1500 includes a processor 1510, a memory 1520, a bus system 1530, and a transmitter 1540.
  • the processor 1510, the memory 1520, and the transmitter 1540 are connected by a bus system 1530 for storing instructions for executing the instructions stored by the memory 1520.
  • the processor 1510 is configured to determine a synchronization reference source, and the type of the synchronization reference source is any one of a global satellite navigation system, a base station, and a user equipment.
  • the transmitter 1540 is configured to send a synchronization signal according to the synchronization reference source, where the synchronization signal includes a first synchronization signal and/or a second synchronization signal, and the sequence of the first synchronization signal and/or the sequence of the second synchronization signal is used to indicate the synchronization reference source. type.
  • the synchronization signal sent by the user equipment can indicate the type of the synchronization reference source, so that other user equipment can be synchronized according to the synchronization.
  • the signal determines the type of the synchronous reference source so that synchronization can be achieved, ensuring optimal communication performance.
  • the processor 1510 may be a CPU, and the processor 1510 may also be other general-purpose processors, DSPs, ASICs, FPGAs, or other programmable logic devices, discrete gates or transistor logic devices, and discrete Hardware components, etc.
  • the general purpose processor may be a microprocessor or the processor or any conventional processor or the like.
  • the memory 1520 can include a read only memory and a random access memory, and is directed to the processor The 1510 provides instructions and data. A portion of the memory 1520 may also include a non-volatile random access memory. For example, the memory 1520 can also store information of the device type.
  • the bus system 1530 may include a power bus, a control bus, a status signal bus, and the like in addition to the data bus. However, for clarity of description, various buses are labeled as bus system 1530 in the figure.
  • each step of the foregoing method may be completed by an integrated logic circuit of hardware in the processor 1510 or an instruction in a form of software.
  • the steps of the method disclosed in the embodiments of the present invention may be directly implemented as a hardware processor, or may be performed by a combination of hardware and software modules in the processor.
  • the software modules can be located in a conventional storage medium such as random access memory, flash memory, read only memory, programmable read only memory, or electrically erasable programmable memory, registers, and the like.
  • the storage medium is located in the memory 1520, and the processor 1510 reads the information in the memory 1520 and performs the steps of the above method in combination with its hardware. To avoid repetition, it will not be described in detail here.
  • At least one sequence of the first synchronization signal is used to indicate the type of the synchronization reference source
  • the first synchronization signal occupies the first symbol and the second symbol, and at least one combination of the sequence used by the first symbol and the sequence used by the second symbol is used to indicate the type of the synchronization reference source; or
  • the sequence set of the second synchronization signal includes at least two sequence subsets, and at least one subset of the at least two sequence subsets is used to indicate a type of the synchronization reference source; or
  • the second synchronization signal includes a third symbol and a fourth symbol, and at least one combination of the sequence used by the third symbol and the sequence used by the fourth symbol is used to indicate the type of the synchronization reference source; or
  • the first synchronization signal occupies the first symbol and the second symbol
  • the second synchronization signal occupies the third symbol and the fourth symbol
  • the sequence used by the first symbol the sequence used by the second symbol
  • the sequence used by the third symbol the fourth symbol
  • At least one combination of the sequences used is used to indicate the type of synchronization reference source.
  • the transmitter 1540 is further configured to send control information, a sequence of the first synchronization signal and/or a sequence of the second synchronization signal, and control information to indicate a type of the synchronization reference source.
  • the transmitter 1540 is further configured to: send control information, where the control information includes at least one of the following information: type auxiliary indication information of the synchronization source, indication information of a transmission period of the synchronization signal, and indication information of whether the synchronization signal is valid. And indication information of whether the synchronization signal is transmitted, indication information of the time-frequency position of the synchronization signal transmission, and indication information of the hop count of the synchronization source.
  • the user equipment 1500 may correspond to a user equipment in the synchronization method 900 according to an embodiment of the present invention and a user equipment 1200 according to an embodiment of the present invention, and each unit/module in the user equipment 1500
  • the above and other operations and/or functions are respectively The corresponding process of the method 900 of FIG. 9 is implemented, and for brevity, no further details are provided herein.
  • the synchronization signal sent by the user equipment can indicate the type of the synchronization reference source, so that other user equipment can be synchronized according to the synchronization.
  • the signal determines the type of the synchronous reference source so that synchronization can be achieved, ensuring optimal communication performance.
  • the term "and/or” is merely an association relationship describing an associated object, indicating that there may be three relationships.
  • a and/or B may indicate that A exists separately, and A and B exist simultaneously, and B cases exist alone.
  • the character "/" in this article generally indicates that the contextual object is an "or" relationship.
  • the disclosed systems, devices, and methods may be implemented in other manners.
  • the device embodiments described above are merely illustrative.
  • the division of cells is only a logical function division.
  • multiple units or components may be combined or integrated. Go to another system, or some features can be ignored or not executed.
  • the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, or an electrical, mechanical or other form of connection.
  • the units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the embodiments of the present invention.
  • each functional unit in various embodiments of the present invention may be integrated in one processing unit
  • each unit may exist physically separately, or two or more units may be integrated into one unit.
  • the above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.
  • Computer readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one location to another.
  • a storage medium may be any available media that can be accessed by a computer.
  • computer readable media may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage media or other magnetic storage device, or can be used for carrying or storing in the form of an instruction or data structure.
  • connection may suitably be a computer readable medium.
  • the software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave. Then, coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, wireless, and microwave are included in the fixing of the associated medium.
  • coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, wireless, and microwave are included in the fixing of the associated medium.
  • a disk and a disc include a compact disc (CD), a laser disc, a compact disc, a digital versatile disc (DVD), a floppy disk, and a Blu-ray disc, wherein the disc is usually magnetically copied, and the disc is The laser is used to optically replicate the data. Combinations of the above should also be included within the scope of the computer readable media.

Abstract

本发明实施例提供了一种同步方法、用户设备和基站。该同步方法包括：用户设备获取同步信息，所述同步信息包括以下信息中的至少一种：同步源的选择参数信息、同步源的指示信息、同步源的优先级信息；所述用户设备接收至少一个同步源发送的第一同步信号；所述用户设备根据所述同步信息和所述第一同步信息确定同步参考源。本发明实施例中，通过获取同步信息，根据同步信息和至少一个同步源的同步信号确定同步参考源，能够实现同步。

Description

同步方法、用户设备和基站 技术领域
本发明涉及通信领域，尤其涉及同步方法、用户设备和基站。
背景技术
近年来，随着智能技术的发展，智能交通、无人驾驶等技术受到了学术界、产业界和各国政府越来越多的关注。为了推动上述产业的发展，车车通信技术和标准是解决上述问题的关键所在。车车通信中的一个基本的问题是：如何在各种复杂的环境下实现车与车之间的高效通信。提高车车通信效率的一种最基本的要求是车车之间保持一定的精度的同步。从而可以减少车车通信的相互干扰并能够提高车车通信时的频谱效率。如图1所示，在车道上的4辆车之间如果能够同步到同一个或一定精度的同一类同步源上，将能提高这个组内各个车间通信的效率。因此，如何确定同步源并实现同步是一个需要解决的问题。
发明内容
本发明实施例提供了一种同步方法、用户设备和基站，能够根据同步信息确定同步参考源，从而能够实现同步。
第一方面，提供了一种同步方法，包括：用户设备获取同步信息，所述同步信息包括以下信息中的至少一种：同步源的选择参数信息、同步源的指示信息、同步源的优先级信息；所述用户设备接收至少一个同步源发送的第一同步信号；所述用户设备根据所述同步信息和所述第一同步信号确定同步参考源。
结合第一方面，在第一种可能的实现方式中，所述用户设备根据所述同步信息和所述第一同步信号确定同步参考源包括：所述用户设备根据所述第一同步信号选择所述至少一个同步源中满足所述选择参数的同步源作为所述同步参考源。
结合第一方面，在第二种可能的实现方式中，所述同步源的指示信息用于指示第一同步源，所述用户设备根据所述同步信息和所述第一同步信号确定同步参考源，包括：所述用户设备根据所述第一同步信号选择所述第一同 步源为所述同步参考源。
结合第一方面，在第三种可能的实现方式中，所述用户设备根据所述同步信息和所述第一同步信号确定同步参考源包括：所述用户设备根据所述优先级信息和所述第一同步信号选择所述至少一个同步源中优先级最高的同步源为所述同步参考源。
结合第一方面，在第四种可能的实现方式中，所述同步源的指示信息用于指示第一同步源，所述用户设备根据所述同步信息和所述第一同步信号确定同步参考源，包括：所述用户设备根据所述第一同步信号确定所述至少一个同步源中包括所述第一同步源；如果所述第一同步源满足预定义的条件，所述用户设备选择所述第一同步源为所述同步参考源；或者，如果所述第一同步源的信号不满足预定义的条件，所述用户设备根据优先级信息选择所述至少一个同步源中除所述第一同步源外优先级最高的第二同步源为所述同步参考源。
结合第一方面或第一种至第四种可能的实现方式中的任一种可能的实现方式，在第五种可能的实现方式中，所述第一同步信号包括第二同步信号和/或第三同步信号，所述用户设备根据所述同步信息确定同步参考源，包括：所述用户设备根据所述第二同步信号的序列和/或所述第三同步信号的序列确定所述至少一个同步源的类型；所述用户设备根据所述同步信息和所述至少一个同步源类型选择所述同步参考源。
结合第五种可能的实现方式，在第六种可能的实现方式中，所述第二同步信号的第一序列、第二序列、和第三序列分别用于指示不同的同步源类型，所述第一序列、所述第二序列和所述第三序列互不相同；或者，
所述第二同步信号占用第一符号和第二符号，所述第一符号使用的序列和所述第二符号使用的序列的多种组合方式用于指示不同的同步源类型；或者，
所述第三同步信号的序列集合包括多个序列子集，所述多个序列子集用于指示不同的同步源类型；或者，
所述第三同步信号占用第三符号和第四符号，所述第三符号使用的序列和所述第四符号使用的序列的多种组合方式用于指示不同的同步源类型；或者，
所述第二同步信号占用第一符号和第二符号，所述第三同步信号占用第 三符号和第四符号，所述第一符号使用的序列、所述第二符号使用的序列、所述第三符号使用的序列和所述第四符号使用的序列的多种组合方式用于指示不同的同步源类型。
结合第一方面或第一种至第四种可能的实现方式中任一种可能的实现方式，在第七种可能的实现方式中，还包括：所述用户设备接收所述至少一个同步源发送的第一控制信息；所述用户设备根据所述同步信息和所述第一同步信号确定同步参考源，包括：所述用户设备根据所述第一控制信息确定所述至少一个同步源的类型；所述用户设备根据所述同步信息、所述第一同步信号和所述至少一个同步源的类型确定所述同步参考源。
结合第一方面或第一种至第六种可能的实现方式中的任一种可能的实现方式，在第八种可能的实现方式中，还包括：所述用户设备接收所述至少一个同步源发送的第一控制信息，所述第一控制信息包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否发送的指示信息、同步信号是否有效的指示信息、同步信号发送的时频位置的指示信息、同步源的跳数的指示信息。
结合第七种可能的实现方式，在第九种可能的实现方式中，所述第一同步信号包括第二同步信号和/或第三同步信号，所述用户设备根据所述第一控制信息确定所述至少一个同步源的类型，包括：所述用户设备根据所述第二同步信号的序列和/或所述第三同步信号的序列、以及所述第一控制信息确定所述至少一个同步源的类型。
结合第一方面或上述任一种可能的实现方式，在第十种可能的实现方式中，所述接收端获取同步信息，包括：所述用户设备接收基站发送的所述同步信息。
结合第十种可能的实现方式，在第十一种可能的实现方式中，在所述用户设备接收所述同步信息之前，所述方法还包括：所述用户设备向所述基站发送所述至少一个同步源的信息，以便所述基站根据所述至少一个同步源的信息确定所述同步信息。
结合第一方面或上述任一种可能的实现方式，在第十二种可能的实现方式中，还包括：所述用户设备根据所述同步参考源发送第四同步信号和/或第二控制信息，所述第四同步信号和/或所述第二控制信息用于指示所述同步参考源的类型。
结合第一方面或上述任一种可能的实现方式，在第十三种可能的实现方式中，还包括：所述用户设备确定所述同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差；所述用户设备根据所述同步参考源的定时基准和所述定时偏差进行通信。
结合第十三种可能的实现方式，在第十四种可能的实现方式中，所述用户设备确定所述同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差，包括：所述用户设备接收基站发送的定时偏差指示信息，所述定时偏差指示用于指示所示定时偏差；所述用户设备根据所述定时偏差指示信息确定所述定时偏差。
结合第十三种可能的实现方式，在第十五种可能的实现方式中，所述用户设备确定所述同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差，包括：所述用户设备获取所述另一链路的同步参考源的定时基准；所述用户设备根据所述同步参考源的定时基准和所述另一链路的同步参考源的定时基准确定所述定时偏差。
第二方面，提供了一种同步方法，包括：基站确定同步信息，所述同步信息包括以下信息中的至少一种：同步源的选择参数信息、同步源的指示信息、同步源的优先级信息；所述基站向用户设备发送所述同步信息。
结合第二方面，在第二方面的第一种可能的实现方式中，还包括：所述基站向所述用户设备发送控制信息，所述控制信息用于指示所述同步参考源的类型和/或标识。
结合第二方面，在第二方面的第二种可能的实现方式中，还包括：所述基站向所使用户设备发送控制信息，所述控制信息包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否有效的指示信息、同步信号是否发送的指示信息、同步信号发送的时频位置的指示信息、同步源的跳数的指示信息。
结合第二方面或第二方面的第一种或第二种可能的实现方式，在第二方面的第三种可能的实现方式中，所述基站确定同步信息包括：所述基站接收所述用户设备发送的至少一个同步源的信息；所述基站根据所述至少一个同步源的信息确定所述同步信息。
结合第二方面或第二方面的上述任一种可能的实现方式，在第二方面的第四种可能的实现方式中，还包括：所述基站向所述用户设备发送定时偏差 指示信息，所述定时偏差指示信息用于指示所述用户设备的同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差。
第三方面，提供了一种同步方法，包括：用户设备确定同步参考源，所述同步参考源的类型为全球卫星导航系统、基站、用户设备中的任意一种；所述用户设备根据所述同步参考源发送同步信号，所述同步信号包括第一同步信号和/或第二同步信号，所述第一同步信号的序列和/或所述第二同步信号的序列用于指示所述同步参考源的类型。
结合第三方面，在第三方面的第一种可能的实现方式中，所述第一同步信号的至少一种序列用于指示所述同步参考源的类型；或者，
所述第一同步信号占用第一符号和第二符号，所述第一符号使用的序列和所述第二符号使用的序列的至少一种组合方式用于指示所述同步参考源的类型；或者，
所述第二同步信号的序列集合包括至少两个序列子集，所述至少两个序列子集中的至少一种子集用于指示所述同步参考源的类型；或者，
所述第二同步信号包括第三符号和第四符号，所述第三符号使用的序列和所述第四符号使用的序列的至少一种组合方式用于指示所述同步参考源的类型；或者，
所述第一同步信号占用第一符号和第二符号，所述第二同步信号占用第三符号和第四符号，所述第一符号使用的序列、所述第二符号使用的序列、所述第三符号使用的序列和所述第四符号使用的序列的至少一种组合方式用于指示所述同步参考源的类型。
结合第三方面或第三方面的第一种可能的实现方式，在第三方面的第二种可能的实现方式中，还包括：所述用户设备发送控制信息，所述第一同步信号的序列和/或所述第二同步信号的序列、以及所述控制信息用于指示所述同步参考源的类型。
结合第三方面或第三方面的第一种可能的实现方式，在第三方面的第三种可能的实现方式中，所述用户设备发送控制信息，所述控制信息包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否有效的指示信息、同步信号是否发送的指示信息、同步信号发送的时频位置的指示信息、同步源的跳数的指示信息。
第四方面，提供了一种用户设备，包括：获取单元，用于获取同步信息， 所述同步信息包括以下信息中的至少一种：同步源的选择参数信息、同步源的指示信息、同步源的优先级信息；收发单元，用于接收至少一个同步源的第一同步信号；确定单元，用于根据所述获取单元获取到的所述同步信息和所述收发单元接收到的所述第一同步信号确定同步参考源。
结合第四方面，在第四方面的第一种可能的实现方式中，所述确定单元具体用于，根据所述第一同步信号选择所述至少一个同步源中满足所述选择参数的同步源作为所述同步参考源。
结合第四方面，在第四方面的第二种可能的实现方式中，所述同步源的指示信息用于指示第一同步源，所述确定单元具体用于，根据所述第一同步信号选择所述第一同步源为所述同步参考源。
结合第四方面，在第四方面的第三种可能的实现方式中，所述确定单元具体用于，所述用户设备根据所述优先级信息和所述第一同步信号选择所述至少一个同步源中优先级最高的同步源为所述同步参考源。
结合第四方面，在第四方面的第四种可能的实现方式中，所述同步源的指示信息用于指示第一同步源，所述确定单元具体用于：根据所述第一同步信号确定所述至少一个同步源中包括所述第一同步源；如果所述第一同步源满足预定义的条件，选择所述第一同步源为所述同步参考源；或者，如果所述第一同步源的信号不满足预定义的条件，根据优先级信息选择所述至少一个同步源中除所述第一同步源外优先级最高的第二同步源为所述同步参考源。
结合第四方面或第四方面的第一种至第四种可能的实现方式中的任一种可能的实现方式，在第四方面的第五种可能的实现方式中，所述第一同步信号包括第二同步信号和/或第三同步信号，所述确定单元具体用于：根据所述第二同步信号的序列和/或所述第三同步信号的序列确定所述至少一个同步源的类型；根据所述同步信息和所述至少一个同步源的类型选择所述同步参考源。
结合第四方面的第五种可能的实现方式，在第四方面的第六种可能的实现方式中，所述第二同步信号的第一序列、第二序列、和第三序列分别用于指示不同的同步源类型，所述第一序列、所述第二序列和所述第三序列互不相同；或者，
所述第二同步信号占用第一符号和第二符号，所述第一符号使用的序列 和所述第二符号使用的序列的多种组合方式用于指示不同的同步源类型；或者，
所述第三同步信号的序列集合包括多个序列子集，所述多个序列子集用于指示不同的同步源类型；或者，
所述第三同步信号占用第三符号和第四符号，所述第三符号使用的序列和所述第四符号使用的序列的多种组合方式用于指示不同的同步源类型；或者，
所述第二同步信号占用第一符号和第二符号，所述第三同步信号占用第三符号和第四符号，所述第一符号使用的序列、所述第二符号使用的序列、所述第三符号使用的序列和所述第四符号使用的序列的多种组合方式用于指示不同的同步源类型。
结合第四方面或第四方面的第一种至第四种可能的实现方式中任一种可能的实现方式，在第四方面的第七种可能的实现方式中，所述收发单元还用于，接收所述至少一个同步源发送的第一控制信息；所述确定单元具体用于：根据所述第一控制信息确定所述至少一个同步源的类型；根据所述同步信息、所述第一同步信号和所述至少一个同步源的类型确定所述同步参考源。
结合第四方面或第四方面的第一种至第六种可能的实现方式中任一种可能的实现方式，在第四方面的第八种可能的实现方式中，所述收发单元还用于，接收所述至少一个同步源发送的第一控制信息，所述第一控制信息包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否发送的指示信息、同步信号是否有效的指示信息、同步信号发送的时频位置的指示信息、同步源的跳数的指示信息。
结合第四方面的第七种可能的实现方式，在第四方面的第九种可能的实现方式中，所述第一同步信号包括第二同步信号和/或第三同步信号，所述确定单元具体用于，根据所述第二同步信号的序列和/或所述第三同步信号的序列、以及所述第一控制信息确定所述至少一个同步源的类型。
结合第四方面或第四方面的上述任一种可能的实现方式，在第四方面的第十种可能的实现方式中，所述获取单元具体用于，接收基站发送的所述同步信息。
结合第四方面的第十种可能的实现方式，在第四方面的第十一种可能的 实现方式中，所述收发单元还用于，在所述获取单元接收所述同步信息之前，向所述基站发送所述至少一个同步源的信息，以便所述基站根据所述至少一个同步源的信息确定所述同步信息。
结合第四方面或第四方面的上述任一种可能的实现方式，在第四方面的第十二种可能的实现方式中，所述收发单元还用于，根据所述同步参考源发送第四同步信号和/或第二控制信息，所述第四同步信号和/或所述第二控制信息用于指示所述同步参考源的类型。
结合第四方面或第四方面的上述任一种可能的实现方式，在第四方面的地十三种可能的实现方式中，所述确定单元还用于，确定所述同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差；所述收发单元还用于，根据所述同步参考源的定时基准和所述确定单元确定的所述定时偏差进行通信。
结合第四方面的第十三种可能的实现方式，在第四方面的第十四种可能的实现方式中，所述收发单元还用于，接收基站发送的定时偏差指示信息，所述定时偏差指示用于指示所示定时偏差；所述确定单元具体用于，根据所述收发单元接收到的所述定时偏差指示信息确定所述定时偏差。
结合第四方面的第十三种可能的实现方式，在第四方面的第十五种可能的实现方式中，所述获取单元还用于，获取所述另一链路的同步参考源的定时基准；所述确定单元具体用于，根据所述同步参考源的定时基准和所述另一链路的同步参考源的定时基准确定所述定时偏差。
第五方面，提供了一种基站，包括：确定单元，用于确定同步信息，所述同步信息包括以下信息中的至少一种：同步源的选择参数信息、同步源的指示信息、同步源的优先级信息；发送单元，用于向用户设备发送所述同步信息。
结合第五方面，在第五方面的第一种可能的实现方式中，所述发送单元还用于，向所述用户设备发送控制信息，所述控制信息用于指示所述同步参考源的类型和/或标识。
结合第五方面，在第五方面的第二种可能的实现方式中，还包括：基站向所述用户设备发送控制信息，所述控制信息包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否有效的指示信息、同步信号是否发送的指示信息、同步信号发送的时频位 置的指示信息、同步源的跳数的指示信息。
结合第五方面或第五方面的第一种或第二种可能的实现方式，在第五方面的第三种可能的实现方式中，还包括：接收单元，用于在所述发送单元向所述用户设备发送所述同步信息之前，接收所述用户设备发送的至少一个同步源的信息；所述确定单元具体用于根据所述接收单元接收到的所述至少一个同步源的信息确定所述同步信息。
结合第五方面或第五方面的上述任一种可能的实现方式，在第五方面的第四种可能的实现方式中，发送单元还用于，向所述用户设备发送定时偏差指示信息，所述定时偏差指示信息用于指示所述用户设备的同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差。
第六方面，提供了一种用户设备，包括：确定单元，用于确定同步参考源，所述同步参考源的类型为全球卫星导航系统、基站、用户设备中的任意一种；发送单元，用于根据所述同步参考源发送同步信号，所述同步信号包括第一同步信号和/或第二同步信号，所述第一同步信号的序列和/或所述第二同步信号的序列用于指示所述同步参考源的类型。
结合第六方面，在第六方面的第一种可能的实现方式中，所述第一同步信号的至少一种序列用于指示所述同步参考源的类型；或者，
所述第一同步信号占用第一符号和第二符号，所述第一符号使用的序列和所述第二符号使用的序列的至少一种组合方式用于指示所述同步参考源的类型；或者，
所述第二同步信号的序列集合包括至少两个序列子集，所述至少两个序列子集中的至少一种子集用于指示所述同步参考源的类型；或者，
所述第二同步信号包括第三符号和第四符号，所述第三符号使用的序列和所述第四符号使用的序列的至少一种组合方式用于指示所述同步参考源的类型；或者，
所述第一同步信号占用第一符号和第二符号，所述第二同步信号占用第三符号和第四符号，所述第一符号使用的序列、所述第二符号使用的序列、所述第三符号使用的序列和所述第四符号使用的序列的至少一种组合方式用于指示所述同步参考源的类型。
结合第六方面或第六方面的第一种可能的实现方式，在第六方面的第二种可能的实现方式中，所述发送单元还用于，发送控制信息，所述第一同步 信号的序列和/或所述第二同步信号的序列、以及所述控制信息用于指示所述同步参考源的类型。
结合第六方面或第六方面的第一种可能的实现方式，在第六方面的第三种可能的实现方式中，所述发送单元还用于，发送控制信息，所述控制信息包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否有效的指示信息、同步信号是否发送的指示信息、同步信号发送的时频位置的指示信息、同步源的跳数的指示信息。
基于上述技术方案，通过获取同步信息，根据同步信息和至少一个同步源发送的同步信号确定同步参考源，能够实现同步。
附图说明
为了更清楚地说明本发明实施例的技术方案，下面将对本发明实施例中所需要使用的附图作简单地介绍，显而易见地，下面所描述的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1是车车通信的示意图。
图2A是根据本发明实施例的系统架构示意图。
图2B是根据本发明实施例的另一系统架构示意图。
图3是根据本发明实施例的同步方法的示意性流程图。
图4是根据本发明另一实施例的同步方法的示意性流程图。
图5是根据本发明实施例的同步信号的示意图。
图6是根据本发明实施例的另一系统架构示意图。
图7是根据本发明实施例的蜂窝链路与设备到设备链路的定时偏差的示意图。
图8是根据本发明又一实施例的同步方法的示意性流程图。
图9是根据本发明又一实施例的同步方法的示意性流程图。
图10是根据本发明实施例的用户设备的示意性框图。
图11是根据本发明实施例的基站的示意性框图。
图12是根据本发明另一实施例的用户设备的示意性框图。
图13是根据本发明另一实施例的用户设备的示意性框图。
图14是根据本发明另一实施例的基站的示意性框图。
图15是根据本发明另一实施例的用户设备的示意性框图。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本发明的一部分实施例，而不是全部实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动的前提下所获得的所有其他实施例，都应属于本发明保护的范围。
在车车通信的车联网系统中，同步源可以是演进型节点B(Evolved Node B，简称eNB)，也可以来自全球导航卫星系统(Global Navigation Satellite System，简称GNSS)，还可以是用户设备(User Equipment，简称UE)本身。
在本发明实施例中，用户设备(User Equipment，简称UE)包括但不限于车载设备、移动台(Mobile Station，简称MS)、移动终端(Mobile Terminal)、移动电话(Mobile Telephone)、手机(handset)及便携设备(portable equipment)等。UE还可以是具有车载设备功能的路侧单元(Road Side Unit，简称RSU)。
基站可以是GSM或CDMA中的基站(Base Transceiver Station，简称BTS)，也可以是WCDMA中的基站(NodeB，简称NB)，还可以是LTE中的演进型基站(Evolutional Node B，简称为eNB)，本发明实施例对此并不限定。基站还可以是具有基站功能的RSU。也可以将基站称为网络，本发明不做限定，在本发明中统一使用基站或eNB为例进行描述。
为描述方便，本发明实施例将以UE和eNB为例进行说明。
下面介绍本发明实施例中的专业术语：
全球导航卫星系统(GNSS)：包括各个国家和地区提供的导航卫星系统，如：中国的北斗，美国的GPS，欧洲的伽利略系统，俄罗斯的GLONASS等。
同步源：指同步接收机直接同步到的同步源，如GNSS，eNB，UE，其中GNSS，eNB和UE可以看作不同的外部参考源或独立参考源；
同步参考源或定时源：指的是一个UE向外发送同步信号时，所参考的同步源或定时的类型，包括：GNSS，eNB，UE。此时的参考源可以看作是非独立的参考源，所不同的是UE向外发送同步信号时，所参考的同步源类型和/或所转发的跳数有所不同。
同步信号：根据同步源的不同，同步信号的特征不同。当同步源为eNB 时，同步信号为来自于eNB发送的下行物理信号的一种或多种。当同步源为UE时，同步信号为来自于UE发送出去的，供其它接收机UE来检测并实现同步的信号，包括设备间的同步信号。当同步源为GNSS时，同步信号为各种制式的卫星系统发射的预定义好的同步信号，以便于卫星接收机的模块来接收并实现时频同步、授时、定位等功能。
图2A是根据本发明实施例的系统架构200示意图。如图2A所示，系统架构200包括：
多个用户设备(UE1,UE2,UE3)，用户设备之间可以相互通信；
一个或多个基站(eNB)，它可以与各个用户设备和/或RSU进行通信；
一个或多个全球导航卫星系统(GNSS)，它可以为其它的网元提供定位与授时、时频同步等信息。
UE1和UE2随着车辆高速移动，UE1和UE2之间相对运功时，具有最大的相对移动速度。上述各个用户设备之间都可以相互通信，通信时可以使用蜂窝链路的频谱，也可以使用5.9GHz附近的智能交通频谱。各用户设备相互通信的技术可以基于LTE协议进行增强，也可以基于D2D技术进行增强，本发明实施例对此并不限定。
图2B为根据本发明实施例的多种类型的同步源的场景示意图。
图2B中UE4，UE5，UE6仅能检测到来自UE发送的同步源。以UE4为例，它能检测到来自UE1，UE2和UE7的同步源。UE1的同步参考源为GNSS，UE1在向外发送同步信号和/或控制信息时，需要向它的接收机指示它的同步参考源类型为GNSS，并且它向外发送时指示它的跳数为第1跳(假设GNSS到UE1的跳数为第0跳)。UE7是以自己为定时基准向外发送的同步源，此时它的定时基准是基于UE7的本地晶振等本地器件来产生的。
图3是根据本发明一个实施例的同步方法300的示意性流程图。如图3所示，同步方法300包括如下内容。
310、UE获取同步信息，同步信息包括以下信息中的至少一种：同步源的选择参数信息、同步源的指示信息、同步源的优先级信息。
同步源的选择参数信息可以包括以下至少一种：同步源的类型、同步源的信号质量的门限值、同步源的跳数的门限值、检测/搜索同步源的时长的门限值、同步源的稳定性门限值。其中信号质量包括参考信号接收功率(Reference Signal Received Power，简称RSRP)，参考信号接收质量 (Reference Signal Received Quality，简称RSRQ)，接收信号强度指示(Received Signal Strength Indication，简称RSSI)中的至少一种。
320、UE接收至少一个同步源发送的第一同步信号。
具体地，UE接收至少一个同步源中每个同步源发送的第一同步信号。
应理解，该至少一个同步源可以包括GNSS、eNB或UE类型的同步源，该至少一个同步源还可以包括多种类型的同步源。
例如，在有网络覆盖的应用场景中，UE可以接收到eNB和GNSS发送的同步信号；在无网络覆盖的应用场景中，UE可以接收到GNSS发送的同步信号；在eNB和GNSS均检测不到的场景下，UE可以接收到UE发送的同步信号。
330、UE根据同步信息和第一同步信号确定同步参考源。
其中，该同步参考源可以是步骤320中UE检测到的至少一个同步源中的一个。但本发明实施例对此并不限定，当UE检测到的至少一个同步源不满足同步信息中的要求时，此时同步参考源为UE本身。
步骤330之后，UE可以根据同步参考源的同步信号与同步参考源进行同步。
同步之后，UE可以与其他设备进行通信。例如，UE可与该同步参考源或基站或其他UE进行通信。
本发明实施例中，通过获取同步信息，根据同步信息和至少一个同步源发送的同步信号确定同步参考源，能够实现同步。
另外，本发明实施例中，UE检测到的至少一个同步源包括多种类型的同步源时，UE能够根据同步信息从多种类型的同步源中确定同步参考源。
可选地，步骤310可以包括：UE接收基站发送的同步信息。
例如，同步信息可以携带在基站下发的信令(如广播消息或专有消息)中。
也就是说，同步信息可以是基站下发的，但本发明实施例对此并不限定，同步信息还可以是预先配置在UE上的，还可以是通过协议预定义的。
可选地，在UE接收所述同步信息之前，方法300还可以包括：
UE向基站发送至少一个同步源的信息，以便基站根据至少一个同步源的信息确定同步信息。
如图4所示，在本发明实施例中，UE可以先上报自己的所检测到的同 步源的信息，基站在收到UE的报告后，向UE发送同步信息。类型以及对应的信号质量。
其中，同步源的信息可以包括以下至少一种：同步源的类型、信号质量、跳数。同步源的信号质量可以包括以下至少一种：同步源的RSRP，RSRQ，RSSI，同步源信号的稳定性，同步参考源的稳定时间，同步源的搜索时间。
UE确定同步源的类型的方法可以参考下文描述的相应内容。为避免重复，这里不再详细描述。
综上，同步信息是可以预先配置在UE上的，也可以是基站主动下发至UE的，也可以是基站在收到UE上报的信息后下发至UE的。
可选地，作为另一实施例，同步信息可以包括同步源的选择参数信息。相应地，步骤330包括：UE根据第一同步信号选择至少一个同步源中满足该选择参数信息的同步源作为同步参考源。
例如，该选择参数信息可以包括：同步参考源需要满足(例如高于或不低于)相应的信号质量的门限值，或者同步参考源的检测/搜索时间低于相应的门限值，或者同步参考源的稳定性满足预定义的条件等。
本发明实施例中，UE需要检测至少一个同步源的信号质量，然后根据同步源的选择参数选择同步参考源。
可选地，作为另一实施例，同步信息可以包括同步源的指示信息，该同步源的指示信息用于指示第一同步源。同步源的指示信息包括以下信息中的至少一种：同步源的标识信息，同步源的类型信息，同步源的当前跳数信息。
相应地，步骤330包括：UE根据第一同步信号选择第一同步源作为同步参考源。
换句话说，基站可以为UE指定同步参考源。
如果同步信息是基站发送的，则UE的同步参考源实际上是由基站选择的，由于基站侧的信息是最安全的，因此本发明实施例有利于做出最佳的决策。
可选地，作为另一实施例，同步信息包括同步源的优先级信息。相应地，步骤330包括：UE根据优先级信息和第一同步信号选择至少一个同步源中优先级最高的同步源作为同步参考源。
同步源的优先级信息可以包括以下至少一种：同步源的类型的优先级信息、同步源的信号质量的优先级信息、同步源的跳数的优先级信息。
同步源的类型的优先级信息是用来指示哪种同步源的优先级最高或者各种同步源的优先级的排列，例如，同步源的优先级可以是GNSS>eNB>UE，还可以是eNB>GNSS>UE。当UE同步到eNB和或GNSS时，同步源的优先级信息还可以为在不同跳数的UE同步源、GNSS和eNB间的排序的指示信息。例如：GNSS>UE(GNSS跳数为1)>eNB>UE(eNB跳数为1)或者，eNB>UE(eNB跳数为1)>GNSS>UE(GNSS跳数为1)等。在此不一一列举。
同步源的信号质量的优先级信息可以指示信号质量好的同步源为优选的同步参考源，同步源的跳数的优先级信息可以指示跳数最少的同步源为优选的同步参考源。
换句话说，同步源的优先级信息可以包括一种优先级信息，还可以包括多种优先级信息。当优先级同时包括多种时，可以按定义的各种优先级间的顺序来作为筛选条件，分步骤来选出同步参考源。例如，有三种优先级C1，C2，C3，他们可以是同步源的类型的优先级信息、同步源的信号质量的优先级信息、同步源的跳数的优先级信息中的各自一种。UE可以先按优先级C1来作为判断条件选择同步参考源，并且进一步地以优先级C2作为判断条件进一步选择同步参考源，优先级C3作为判断条件进一步选择同步参考源。上述三个步骤，任意一个步骤选择确定的同步源即可以认为同步参考源选择成功。如果前面的条件没有选择成功，则继续按后面的优先级信息来选择，直到选择出确定的同步参考源为止。
换句话说，如果UE根据一种优先级信息无法筛选出一个同步源作为同步参考源时，UE可以按照一定的先后顺序根据多种优先级信息逐层筛选，以确定一个同步源作为同步参考源。例如，当按照第一种优先级信息选择出多个同步源时，可以进一步按照第二种优先级信息继续选择出一个同步源作为同步参考源。当然，如果按照第二种优先级信息选出的同步源的数量仍大于1个时，还可以继续按照其他优先级信息继续选择或者随机选择，在此不再赘述。当存在多种优先级信息时，本发明实施例中对UE选择同步参考源时使用的多种优先级信息的先后顺序不做限定。
应注意，当所选出的同步参考源数量大于1个时，UE也可以按照随机的方式选择最终使用的同步参考源。
例如，UE检测到M1个同步源，首先按照同步源的类型的优先级信息，例如eNB>GNSS>UE，从M1个同步源中选择M2个eNB的同步源；接着， 从M2个同步源中选择信号质量满足预定义条件的同步源作为同步参考源。当从M2个同步源中有M3个同步源的信号质量相同时，在该M3个同步源分别为M3个UE转发的同步参考源的应用场景中，进一步地，UE还可以从M3个同步源中选择UE转发的跳数最少的一个同步源作为同步参考源。
再如，如图2B所示的UE1的同步参考源为GNSS，如果UE2发送时使用的同步参考源也为GNSS，则UE4在收到UE1和UE2发送的同步信息时，因为同步参考源相同，则可以根据跳数和信号质量来选。这里跳数也正好相同，还可以根据信号质量来选。比如，如果UE1到UE4的损耗更小的话，则UE4可以选择UE1作为自己的同步源。类似的，UE5能收到来自UE2，UE4和UE6发送的同步信息，UE5需要从UE2，UE4和UE6中来选择一个同步源作为同步参考源。如果按跳数最小的准则，则可以选择UE2作为自己的同步源(如果UE2选择了GNSS或eNB作为自己的同步源的话)。
可选地，作为另一实施例，同步源的指示信息用于指示第一同步源。相应地，步骤330可以包括：
UE根据第一同步信号确定至少一个同步源中包括第一同步源；
如果第一同步源满足预定义的条件，UE选择第一同步源为同步参考源；或者，
如果第一同步源的信号不满足预定义的条件，UE根据优先级信息选择至少一个同步源中除第一同步源外优先级最高的第二同步源为同步参考源。
其中，预定仪的条件可以包括以下至少一种：第二同步源的信号质量满足预设的门限值、第二同步源的跳数满足预设的门限值、第二同步源的检测/搜索时长满足预设的门限值、第二同步源的类型为预设的类型。
预定义的条件可以是预先配置在UE上的，也可以是携带在同步信息中的，还可以是UE通过其他方式获取的，本发明实施例对此并不限定。类似地，优先级信息可以是预先配置在UE上的，也可以是携带在同步信息中的，还可以是UE通过其他方式获取的，本发明实施例对此并不限定。
换句话说，如果同步信息中的同步源的指示信息指示以GNSS为同步参考源。则当UE检测到多个以及多种来自不同类型的同步源时，UE首先判断是否检测到了GNSS；如果检测到的GNSS信号满足预定义的条件，则UE直接以GNSS为同步参考源向外发送同步信号，并且向它的接收机指示使用的同步参考源为GNSS，并且指示它发送的同步源的跳数。如果没有检 测到GNSS，或者如果检测到的GNSS信号不满足预定义的条件，则看它检测到的其他同步源或者UE转发的同步源/同步参考源类型、信号质量、跳数等信息，根据优先级信息来选择同步参考源。根据优先级信息选择同步参考源的描述可以参考上文，在此不再赘述。
下面结合场景一和场景二的具体例子详细描述本发明实施例的方法：
场景一、GNSS为优选的同步源。适用于网络外，和/或网络内eNB配置了GNSS为优选同步源的场景。
步骤1：如果获取到的同步信息指示要求优选以GNSS为同步源。则当接收机检测到多个以及多种来自不同类型的同步源时，接收机首先判断它是否检测到了GNSS，并且检测到的GNSS是否满足预定义的条件。
步骤2：如果检测到的GNSS信号满足预定义的条件，则接收机直接以GNSS为同步参考源，并且向外发送同步信号。并且向它的接收机指示使用的同步参考源为GNSS，并且指示它的发送的同步源跳数。
步骤3：如果没有检测到GNSS，或者如果检测到的GNSS信号不满足预定义的条件，则看它检测到的其他UE转发的同步源/同步参考源类型、信号质量、跳数等信息，来按以下准则排序来选择同步源(此时的同步源可以包括GNSS和UE，而UE转发的定时参考源可以包括eNB，GNSS，UE中的一种)：
1)、同步源类型第一优先级，信号质量为第二优先级，跳数为第三优先级：
例如，UE同时收到多个UE转发的同步参考源，它们分别来自M1个eNB的同步参考源，M2个GNSS的同步参考源，M3个UE的同步参考源。
如果同步参考源的类型为第一优先级，如优先级的顺序为GNSS>eNB>UE，则从M2个GNSS的同步参考源中找出信号质量满足预定义条件的M21个同步参考源，然后再从M21中找跳数最小的同步参考源作为自己的同步参考源；
第二优先级和第三优先级的先后顺序可以互换。例如，还可以从M2个GNSS的同步参考源中找出跳数满足预定义条件的M21个同步参考源，然后再从M21个同步参考源中找出信号质量最好的同步参考源。
2)、信号质量为第一优先级，类型为第二优先级，跳数为第三种优先级：
例如，UE同时收到多个UE转发的同步参考源，它们分别来自M1个 eNB的同步参考源，M2个GNSS的同步参考源，M3个UE的同步参考源。
如果信号质量第一优先级，则从所有的同步参考源中找出M4个信号质量满足预定义条件的同步参考源，然后再从这M4个同步参考源中找出M41个优先级最高的类型的同步参考源，最后再从M41个同步参考源中找出M411个跳数最小的同步参考源。
同样，第二种优先级和第三种优先级的先后顺序可以互换。
3)、更小/最小跳数为第一优先级，类型为第二种优先级，跳数为第三种优先级：
例如，UE同时收到多个UE转发的同步参考源，它们分别来自M1个eNB的同步参考源，M2个GNSS的同步参考源，M3个UE的同步参考源。
如果更小/最小跳数为第一优先级，则从所有的同步参考源中找出M4个跳数最小的同步参考源，然后再从这M4个同步参考源中找出M41个优先级最高的类型的同步参考源，最后再从M41个同步参考源中找出M411个信号质量满足预定义条件的同步参考源。
同样，第二优先级和第三优先级的先后顺序可以互换。
场景二、eNB为优选的同步源。适用于网络内，和/或网络外有eNB的场景。
步骤1：如果获取到的同步信息指示按预定义的条件来选择GNSS或eNB为同步参考源。
步骤2：UE根据它检测到的其他同步源(eNB和/或GNSS)、以及其他UE转发的同步源/同步参考源类型、信号质量、跳数等信息，来按以下准则来选择同步源(此时的同步源/同步参考源可以包括eNB、GNSS、UE中的一种)：
1)、同步源类型为第一优先级，第二优先级可以为信号质量和跳数中的任意一种；
2)信号质量为第一优先级，第二优先级可以为同步源类型和跳数中的任意一种；
3)跳数为第一优先级,第二优先级可以为信号质量和同步源类型的任意一种。
根据上面的准确确定同步参考源的具体过程可以参考场景一的相关描述，为简洁，在此不再赘述。
需要说明的是，当UE检测到的同步源中包括独立同步源，如GNSS、eNB时，UE可以优先选择GNSS或eNB作为同步参考源。如果UE检测到除其它同步源UE发送的同步信号和/或控制信息外还检测到其他同步参考源(eNB和/或GNSS)，则UE优先从其他同步参考源(eNB和/或GNSS)中确定自己的同步参考源。
需要说明的是同步源的优先级信息并不限于以上所描述的内容，例如，同步源的优先级信息还可以包括同步源的检测/搜索时长的优先级信息、同步源的稳定性的优先级信息等。
可选地，作为另一实施例，第一同步信号包括第二同步信号和/或第三同步信号。
相应地，步骤330包括：
UE根据第二同步信号的序列和/或第三同步信号的序列确定至少一个同步源的类型；
UE根据同步信息和至少一个同步源的类型确定同步参考源。
需要说明的是，本发明实施例中第一同步信号可以包括第二同步信号和/或第三同步信号。即第二同步信号和第三同步信号两者可以同时出现，也可以只出现其中的一种。其中第二同步信号由ZC(Zadoff-Chu)序列生成，第三同步信号由与长期演进(Long Term Evolution，简称LTE)系统中类似的两个m序列生成。对应现有技术，第二同步信号可以是设备到设备(Device to Device，简称D2D)系统中的主D2D同步信号(Primary D2D Synchronization Signal，简称PD2DSS)，或者LTE中的主同步信号(Primary Synchronization Signal，简称PSS)，也可以是由其他长度的ZC序列生成的信号。第三同步信号可以是D2D中的从D2D同步信号(Secondary D2D Synchronization Signal，简称SD2DSS)，也可以是LTE中的辅同步信号(Secondary Synchronization Signal，简称SSS)，可以是由其它长度的m序列生成的序列。对于第二同步信号和第三同步信号所使用的调制方式，可以是正交频分复用(Orthogonal Frequency Division Multiplexing，简称OFDM)，也可以是单载波频分多址(Single-carrier Frequency-Division Multiple Access，简称SC-FDMA)，本发明实施例对此不做限定。可以用不同的根序列号来表示不同的第一同步序列，如第一同步序列26，37等。
本发明下面的实施例中，使用了D2D系统中对同步信号的术语，但如 上，本发明实施的方法并不限于D2D系统。本发明实施例是用不同的第二同步信号的序列或第三同步信号的序列的组合方式来指示同步源的类型，以便于同步源的发射机和同步源的接收机来使用。
可选地，UE可以根据第一同步信号中的第二同步信号的序列确定至少一个同步源的类型。
在一种可能的实现方式中，第二同步信号的第一序列、第二序列、和第三序列分别用于指示不同的同步源类型，第一序列、第二序列和第三序列互不相同。
例如，第一序列用于指示同步源的类型为GNSS，第二序列用于指示同步源的类型为基站，第三序列用于指示同步源的类型为UE。
现有的D2D的同步序列的设计过程中PD2DSS有两个序列，其由ZC序列生成，对应的根序列号分别为26和37，它们分别是对应同步源来自eNB(有网络的场景)以及同步源来自UE(无网络的场景)。其对应的同步源的ID编号分别为：
PD2DSS序列26，对应的标识为id_net，其序列标识的集合为{0,167}；
PD2DSS序列37，对应的标识为id_oon，其序列标识的集合为{168,335}。
例如，第一序列为x，第二序列为序列26，第三序列为序列37。其中，x为PD2DSS对应的长为63的ZC序列的根序列的值，其取值范围为1～62，并且与它不同于序列26和37并且与序列26和37有较低的互相关值。
例如，序列x可以为：序列29，31，23，25，34，32，40，38等，对应于同步参考源的类型为GNSS。或者用来生成PD2DSS的序列x的根序列号也可以是别的组，例如{25,29,34}，本发明对此不做限制。它对应的同步源ID编号为：
PD2DSS序列x，对应的标识为id_gnss，序列标识集合为{336,504}。
PD2DSS序列x指示同步源类型为GNSS，意味着，对同步源的发射机而言，如果它选择的同步参考源为GNSS，则其发射PD2DSS信号即为序列x，并且对应的同步源的序列标识集合为{336,504}。对接收机而言，如果它检测到同步源发送的PD2DSS序列为26，37，x中的任意一种，则对应解释为接收到来自相应的同步源。
通过使用新增加的PD2D序列x来指示同步参考源GNSS，不影响现有的D2DSS的信号发送和生成，能够与现有技术完全兼容。
应注意，在本发明实施例中并不限定PD2DSS序列26、37、x对应的同步源的类型。例如，PD2DSS序列26也可以用于指示同步源的类型为UE，PD2DSS序列37也可以用于指示同步源的类型为GNSS，PD2DSS序列x也可以用于指示同步源的类型为eNB。
在另一种可能的实现方式中，第二同步信号包括第一符号和第二符号，第一符号使用的序列和第二符号使用的序列的多种组合方式用于指示不同的同步源类型。
图5所示为D2D通信中同步信号和PSBCH信道的示意图。如图5所示，D2D同步信号D2DSS由PD2DSS和SD2DSS两部分组成，白色带横线的部分是用来放置PSBCH的符号，其它两个解调参考信号(Demodulation Reference Signal，简称DMRS)是用于PSBCH做解调用的参考信号，最后的一个符号为空出来不发的符号，用GAP来表示。
如图5所示，PD2DSS占用符号1和符号2进行传输。符号1使用的序列和符号2使用的序列的多种组合方式可以用于指示不同的同步源类型。例如：
{PD2DSS符号1序列，PD2DSS符号2序列}＝{26,26}→id_net:{0,167}；
{PD2DSS符号1序列，PD2DSS符号2序列}＝{26,37}→id_gnss:{168,335}；
和/或，
{PD2DSS符号1序列，PD2DSS符号2序列}＝{37,26}→id_oon:{336,504}；
{PD2DSS符号1序列，PD2DSS符号2序列}＝{37,37}→id_gnss:{505,772}。
上面的{26,37}→id_gnss:{168,335}除了指示同步源为GNSS外，还可以进一步地指示为有网络时使用的同步参考为GNSS。{37,37}→id_gnss:{505,772}除了指示使用的同步参考源为GNSS外，还可以进一步地指示为无网络时使用的同步参考源为GNSS。
本发明实施例中没有增加D2DSS待检测的序列的数量，但是利用了PD2DSS占用了两个符号的特点，分别做不同的组合映射，从而用来指示不同的同步参考源的类型。
可选地，UE还可以根据第三同步信号的序列确定至少一个同步源的类型。
在一种可能的实现方式中，第三同步信号的序列集合包括至少两个序列子集，至少两个序列子集用于指示不同的同步源类型。
本发明实施例中，第二同步信号的序列可以与现有技术相同，将第三同步信号的序列的集合分成至少两个子集，用于指示不同的同步源类型。例如：
PD2DSS序列26，SD2DSS对应序列第一子集指示同步源的类型为eNB，SD2DSS对应序列第二子集指示同步参考源的类型为GNSS；和/或
PD2DSS序列37，SD2DSS对应序列第一子集指示同步源的类型为同步源为UE，SD2DSS对应序列第二子集指示同步源的类型为GNSS。
可以采用下面描述的方法1和方法2将SD2DSS的序列的集合分为两个子集。
方法1、将现有的{0，167}的从同步序列分成两个子集，两个子集可以连续的取SD2DSS的编号的序列，如{0，x}为第一子集，{x+1,167}为第二子集。也可以间隔地取，本发明实施例对此不做限定。两个子集的配置信息可以是基站指示的，也可以是预定义的。例如：
PD2DSS序列26，同步参考源为eNB对应的标识为id_net，其SD2DSS序列的集合为{0,x}，同步参考源为GNSS对应的标识为id_gnss，其SD2DSS序列的集合为{x+1,167}；和/或，
PD2DSS序列37，同步参考源为UE对应的标识为id_oon，其SD2DSS序列的集合为{168,y}，同步参考源为GNSS对应的标识为id_gnss，其SD2DSS序列的集合为{y+1,335}。
同步源的标识集合还有其他的映射方法，这里不一一列举，只要GNSS对应SD2DSS序列的集合中的一个子集即可。
本发明实施例中，由于没有新增加PD2DSS序列，也没有增加总的SD2DSS的序列数，因此不会增加接收机的检测复杂度。
方法2、现有的SD2DSS的序列{0,167}不变，扩展SD2DSS序列的个数，如扩展SD2DSS序列为{0,335}。需要说明的是，SD2DSS序列的生成方式与现有的D2D协议相同，是由两个长为31的m序列生成的。理论上，两个长为31的m序列，可以总共至少有31*30/2＝465个不同的从同步序列。因此是可以再取出目前LTE以及D2D系统中没有使用的167编号之外的从 同步序列，用以指示新的同步源类型。例如：
PD2DSS序列26，同步参考源为eNB对应的标识为id_net，其SD2DSS序列的集合为{0,167}，同步参考源为GNSS对应的标识为id_gnss，其SD2DSS序列的集合为{167,335}；和/或
PD2DSS序列37，同步参考源为UE对应的标识为id_oon，其SD2DSS序列的集合为{336,503}，同步参考源为GNSS对应的标识为id_gnss，其SD2DSS序列的集合为{504,771}。
扩展的SD2DSS序列集合的信息可以是基站配置，也可以是预定义的。
本发明实施例中没有新增加PD2DSS序列，扩展了SD2DSS的可用序列，用来指示不同的同步源类型，从而提供了可供识别的同步源数量。
在另一种可能的实现方式中，第三同步信号包括第三符号和第四符号，第三符号使用的序列和第四符号使用的序列的多种组合方式用于指示同步源的不同的同步源类型。
如图4所示，SD2DSS占用符号1和符号2进行传输。符号1使用的序列和符号2使用的序列的多种组合方式可以用于指示不同的同步源类型。例如：
PD2DSS＝26，{SD2DSS符号1序列，SD2DSS符号2序列}＝{x,x}→id_net:{0,167}；
PD2DSS＝26，{SD2DSS符号1序列，SD2DSS符号2序列}＝{x,y}→id_gnss:{168,335}；
和/或：
PD2DSS＝37，{SD2DSS符号1序列，SD2DSS符号2序列}＝{y,y}→id_oon:{336,504}；
PD2DSS＝37，{SD2DSS符号1序列，SD2DSS符号2序列}＝{x,y}→id_gnss:{505,772}。
其中x和y都是SD2DSS序列在集合{0,167}中的任意一个序列，也可以是{0,335}集合中的任意一个序列，并且x和y对应的SD2DSS序列的编号不同。
本发明实施例中没有增加同步信号待检测的序列的数量，但是利用了第三同步信号占用两个符号的特点，分别做不同的组合映射，从而用来指示不同的同步参考源的类型。
UE还可以根据第二同步信号的序列和第三同步信号的序列的组合方式确定同步源的类型。
例如，第一符号使用的序列、第二符号使用的序列、第三符号使用的序列和第四符号使用的序列的多种组合方式用于指示不同的同步源类型；或者，
第二同步信号的序列、第三同步信号的序列的不同组合用于指示不同的同步源类型；或者，
第二同步信号的序列、第三同步信号占用的两个符号分别使用的序列的不同组合用于指示不同的同步源类型；或者，
第二同步信号占用的两个符号分别使用的序列、第三同步信号使用的序列的不同组合用于指示不同的同步源类型。
也就是说，还可以结合第二同步信号和第三同步信号分别占用两个符号的特点，分别进行不同的组合映射，从而来指示不同的同步参考源的类型。为简洁，本发明实施例对此不再赘述。
可选地，作为另一实施例，方法300还包括：UE接收至少一个同步源发送的第一控制信息。
例如，UE接收至少一个同步源中每个同步源发送的第一控制信息。
其中，控制信息可以包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号是否有效的指示信息、同步信号是否发送的指示信息、同步信号的发送周期的指示信息、同步信号发送的时频位置的指示信息、同步源的跳数的指示信息。
当控制信息是从UE发射时，控制信息的承载方式可以是多种的，例如，可以通过控制信道如物理边链路广播信道(Physical Sidelink Broadcast Channel，简称PSBCH)中的显示字段来显式或隐式地指示，或者通过PSBCH信道中的解调参考信号(Demodulation Reference Signal，简称DMRS)来捎带指示，还可以使用PSBCH数据包的循环冗余校验(Cyclic Redundancy Check，简称CRC)掩码来隐式指示。例如还可以通过UE发送的业务数据的控制信道，如物理边链路控制信道(Physical Sidelink Control Channel，简称PSCCH)信道来指示。还可以是通过UE发射的业务信道来指示，如物理边链路共享信道(Physical Sidelink Shared Channel，简称PSSCH)。本发明对此不做限定。
同步源的跳数的指示信息用于指示UE类型同步源到其转发的同步参考源当前的跳数。
例如，UE能够检测到有效的GNSS时，和/或接收到eNB发送的信令，指示UE使用GNSS作为同步参考源或作为优选的同步参考源时，UE使用GNSS作为同步参考源，同步到GNSS上。
如果UE已经直接同步到GNSS上，则UE直接接收控制信息即可，而不需要接收D2DSS信号；如果接收机已经同步到以GNSS为同步参考源的同步源上，则接收机只需要检测少量的D2DSS，然后直接接收控制信息即可。
当UE检测到GNSS时，UE作为同步源可以发送控制信息，同时以更稀疏的方式发送同步信号或者不发送同步信号。其中，更稀疏的方式发送同步信号，包括：只在同步信号子帧中开始的部分子帧中发送同步信号，后面的子帧不发送同步信号；或者以比PSBCH周期(如40ms)更大的周期，如80ms，120ms，160ms等的方式发送同步信号；或者直接不发送同步信号，只发送控制信息。
本发明实施例中，当UE检测到GNSS时，UE使用GNSS作为同步参考源，此时UE可以不发送同步信号或少发送同步信号，这样能够减少不必要的信号发射，同时也能够减少其他UE对同步信号的不必要的检测，减少了功率消耗，降低了UE的复杂度。
可选地，步骤330可以包括：
所述UE根据第一控制信息确定至少一个同步源的类型；
所述UE根据同步信息、第一同步信号和至少一个同步源的类型确定同步参考源。
可选地，UE还可以根据第二同步信号的序列和/或第三同步信号的序列、以及第一控制信息确定至少一个同步源的类型。
例如，控制信息可以为1比特的指示信息，用Flag表示：
PD2DSS＝26,Flag＝0,{id_net_eNB}:{0,167}，表示同步参考源优选为eNB；
PD2DSS＝26,Flag＝1,{id_net_GNSS}:{168,335}，表示同步参考源在有eNB的条件下，优选为GNSS；
PD2DSS＝37,Flag＝0,{id_oon_nGNSS}:{336,504}，表示同步参考源在 无eNB的条件下，优选为GNSS；
PD2DSS＝37,Flag＝1,{id_oon_wGNSS}:{505,772}，表示同步参考源在无eNB的条件下，优选为UE。
具体地，控制信息可以在PSBCH信道中的显示字段承载，也可以通过PSBCH信道中的其他字段或PSBCH信道上的DMRS或CRC来隐式指示。本发明实施例对此不做限定。
本发明实施例中，不需要修改D2DSS序列和信号的发送方法本身，通过联合控制信息一起来指示同步源的类型。
应注意，UE根据步骤330确定的同步参考源发送同步信号和/或控制信息之后，如果检测到了另一新同步源，且该新同步源的优先级高于该同步参考源的优先级，则UE以该新同步源作为新的同步参考源发送新的同步信号和/或控制信息。例如，图2B中UE7是一个相对比较孤立的UE，如果它能收到UE4发的同步信息，或者能够在后续检测到GNSS，则它可以同步到UE4或GNSS上。
可选地，作为另一实施例，方法300还可以包括：UE根据同步参考源发送第二同步信号和/或第二控制信息，第二同步信号和/或第二控制信息用于指示同步参考源的类型。
此时，UE本身可以作为同步源向外发送同步信号和/或控制信息。
应理解，第二同步信号和/或第二控制信息指示同步参考源的类型的具体方式可以参考前面第一同步信号和/或第一控制信息指示同步参考源的方法，为避免重复，在此不再赘述。
需要说明的是，不是每一个UE都需要做同步源，它只有满足一定的条件时才会自发成为一个同步源。例如，UE检测到同步源满足以下至少一项：
UE检测到的其它同步源的信号质量都不满足预定义的门限值；
UE检测到的其它同步源的信号质量虽然有满足预定义的门限值的同步源，但是来自其它同步源的跳数大于预定义的门限值。
此时，UE本身会成为一个同步源，并发送同步信号和/或控制信息。
同步信息还可以包括以下至少一种信息：同步信号使用的同步序列的配置信息；同步信号和/或控制信息的发射频域位置信息；同步信号和/或控制信息的发射时域位置信息；同步信号和/或控制信息的发射功率信息。
具体地，UE根据同步信息发送同步信号和/或控制信息。
可选地，作为另一实施例，方法300还可以包括：
UE确定同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差；
UE根据同步参考源的定时基准和定时偏差进行通信。
如图6所示，当同时存在设备到设备的链路以及蜂窝链路时，因为有GNSS的存在，设备到设备其定时和同步基准可以以GNSS为统一的同步源，以UTC时间为统一的时间基准。而eNB之间，尤其是异步的eNB之间，其定时的基准肯定会与设备到设备之间的定时基准不同。
带来的直接问题是，如图7所示，蜂窝链路之间的系统帧号的时间起始位置与设备到设备链路的系统帧号的时间的起始位置不同。这种不同，会给基站的调度信令与设备到设备链路之间的映射产生理解不一致的问题。如图7，因为蜂窝链路与设备到设备链路间的定时是完全异步的，则基站配置下来的设备到设备间的传输参数的对应关系可能不唯一。
因此，本发明实施例中，UE通过确定同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差，并根据同步参考源的定时基准和定时偏差进行通信，能够解决同时存在D2D链路以及蜂窝链路的情况下，两种链路之间的定时基准不同的问题。
可选地，UE可以根据基站的指示确定同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差。
具体地，UE确定同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差，包括：
UE接收基站发送的定时偏差指示信息，定时偏差指示信息用于指示定时偏差；
UE根据定时偏差指示信息确定定时偏差。
其中，定时偏差指示信息可以包括同步参考源的定时基准与另一链路的同步参考源的定时基准之间的偏差值；
例如，基站通过信令向它服务的UE指示本小区以及相邻小区下蜂窝链路与设备到设备链路的定时偏差时，指示信息包括：
{小区标识ID，蜂窝链路与设备到设备链路的定时偏差值}；或者，
{小区标识ID，蜂窝链路与预定义的定时间基准间的偏差值}。
其中，预定义的定时间基准可以是UTC定时，也可以是基于UTC定时 预定义的设备到设备系统帧号起始位置或最大可指示的帧的起始位置。系统帧以及最大可指示的帧的长度都是预定义的。如在LTE中，系统帧号的长度为10ms，最大可指示的帧的长度是1024个无线帧，即10.24s。
首先，在设备到设备的链路上，需在UTC时间上预定义设备到设备链路的无线帧号的起启时间，例如，设备到设备链路上的无线帧0的开始时间为：
Tstart＝Mod(tUTC+t1,N)，
其中Tstart是设备到设备链路上的无线帧0的开始时间；tUTC为当前的UTC时间；t1是一个偏差值。上述参数中，N是预定义的常数，N为1024时所有时间的单位为10ms，N为10240时所有时间单位为1ms。Mod是取余运算符。
基站给设备发送的信令和/或配置信息是基于它的系统帧号的起启时间的帧号的时间TeNB来配置的。有了Tstart的预定义的计算规则后，基站可以根据自己的定时把两个链路之间的定时偏差值(offset)配置给UE。UE和这个offset值之后，就可以将基站配置的设备到设备链路的发射信息映射到自己的收发参数上来。例如，如果offset值为100ms，则接收到eNB指示D2D链路的配置信息为：在子帧3上发送设备到设备数据，则UE对应到它的链路上的时间即为在设备到设备链路上的子帧103上发送设备到设备的数据。
可选地，UE也可以根据预定义的规则确定同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差。
具体地，UE确定同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差，包括：
UE获取另一链路的同步参考源的定时基准；
UE根据同步参考源的定时基准和另一链路的同步参考源的定时基准确定定时偏差。
例如，UE通过对基站的同步过程，获取到相邻小区的定时的列表，然后UE如果同步到GNSS上的话，则按预定义的基于GNSS的定时基准来与检测到的相邻小区的定时来计算各个小区UE自己使用的定时偏差值。
本发明实施例中设备到设备链路上的无线帧0的开始时间Tstart需要预定义。同时也要定义Tstart与TeNB之间的偏差的确定规则，例如，按如下的 规则确定offset的值：
offset＝Mod(Tstart–TeNB,N),N是预定义的常数，N为1024时所有时间的单位为10ms，N为10240时所有时间单位为1ms，Mod是取余运算符。
综上，UE可以根据上面描述的两种方式确定两个链路之间的定时偏差，从而获取到它的发射和接收参数的信令。
图8是根据本发明实施例的同步方法800的示意性流程图。方法800与方法300相对应，在此将适当省略相应的内容。如图8所示，方法800包括如下内容。
810、基站确定同步信息，同步信息包括以下信息中的至少一种：同步源的选择参数信息、同步源的指示信息、同步源的优先级信息；
820、基站向UE发送同步信息。
UE接收到同步信息后，可以根据该同步信息确定同步参考源。
本发明实施例中，通过向用户设备发送同步信息，使得用户设备能够根据同步信息确定同步参考源，从而能够实现同步，保证了最佳的通信性能。
可选地，作为另一实施例，同步方法800还包括：
基站向用户设备发送控制信息，控制信息用于确定同步参考源的类型和/或标识。
可选地，作为另一实施例，同步方法800还包括：基站向用户设备发送控制信息，控制信息包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否有效的指示信息、同步信号是否发送的指示信息、同步信号发送的时频位置的指示信息、同步源的跳数的指示信息。
同步源的跳数的指示信息用于指示同步源的最大跳数。UE可以在该最大跳数以内转发该同步源。
可选地，步骤810具体包括：
基站接收用户设备发送的至少一个同步源的信息；
基站根据至少一个同步源的信息确定同步信息。
可选地，作为另一实施例，同步方法800还包括：
基站向用户设备发送定时偏差指示信息，定时偏差指示信息用于指示用户设备的同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差。
本发明实施例中，通过向用户设备发送同步信息，使得用户设备能够根据同步信息确定同步参考源，从而能够实现同步，保证了最佳的通信性能。
图9所示为根据本发明另一实施例的同步方法900的示意性流程图。方法900与方法300相对应，在此将适当省略相应的内容。如图9所示，方法900包括如下内容。
910、UE确定同步参考源，同步参考源的类型为GNSS、基站、UE中的任意一种。
应理解，该同步参考源可以为GNSS、基站或其他UE，还可以为UE本身。
920、UE根据同步参考源发送同步信号，同步信号包括第一同步信号和/或第二同步信号，第一同步信号的序列和/或第二同步信号的序列用于指示同步参考源的类型。
此时，UE可以作为同步源。
本发明实施例中，当UE的同步参考源的类型为GNSS、基站、UE中的任意一种时，用户设备发送的同步信号能够指示该同步参考源的类型，使得其他用户设备能够根据该同步信号确定同步参考源，从而能够实现同步，保证了最佳的通信性能。
具体地，第一同步信号的序列和/或第二同步信号的序列用于指示同步参考源的类型包括：
第一同步信号的至少一种序列用于指示同步参考源的类型；或者，
第一同步信号占用第一符号和第二符号，第一符号使用的序列和第二符号使用的序列的至少一种组合方式用于指示同步参考源的类型；或者，
第二同步信号的序列集合包括至少两个序列子集，至少两个序列子集中的至少一种子集用于指示同步参考源的类型；或者，
第二同步信号包括第三符号和第四符号，第三符号使用的序列和第四符号使用的序列的至少一种组合方式用于指示同步参考源的类型；或者，
第一同步信号占用第一符号和第二符号，第二同步信号占用第三符号和第四符号，第一符号使用的序列、第二符号使用的序列、第三符号使用的序列和第四符号使用的序列的至少一种组合方式用于指示同步参考源的类型。
可选地，作为另一实施例，方法900还包括：
用户设备发送控制信息，其中控制信息包括以下信息中的至少一种：同 步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否有效的指示信息、同步信号是否发送的指示信息、同步信号发送的时频位置的指示信息、同步源的跳数的指示信息。
其中同步源的跳数的指示信息用于指示用户设备到同步参考源当前的跳数。
可选地，第一同步信号的序列和/或第二同步信号的序列、以及控制信息用于指示同步参考源的类型。
应理解，本发明实施例中，步骤910中UE确定同步参考源的方法可以参考方法300中的UE确定同步参考源的方法，为避免重复，在此不再赘述。
本发明实施例中，当UE的同步参考源的类型为GNSS、基站、UE中的任意一种时，用户设备发送的同步信号能够指示该同步参考源的类型，使得其他用户设备能够根据该同步信号确定同步参考源，从而能够实现同步，保证了最佳的通信性能。
下面结合图10至图15，详细描述根据本发明实施例的用户设备和基站。
图10是根据本发明实施例的用户设备1000的示意性框图。如图10所示，用户设备1000包括：获取单元1010、收发单元1020和确定单元1030。
获取单元1010，用于获取同步信息，同步信息包括以下信息中的至少一种：同步源的选择参数信息、同步源的指示信息、同步源的优先级信息；
收发单元1020，用于接收至少一个同步源发送的第一同步信号；
确定单元1030，用于根据获取单元1010获取到的同步信息和收发单元1020接收到的第一同步信号确定同步参考源。
本发明实施例中，通过获取同步信息，根据同步信息和至少一个同步源发送的同步信号确定同步参考源，能够实现同步。
可选地，确定单元1030具体用于，根据第一同步信号选择至少一个同步源中满足选择参数的同步源作为同步参考源。
可选地，同步源的指示信息用于指示第一同步源，确定单元1030具体用于，根据第一同步信号选择第一同步源为同步参考源。
可选地，确定单元1030具体用于，用户设备根据优先级信息和第一同步信号选择至少一个同步源中优先级最高的同步源为同步参考源。
可选地，同步源的指示信息用于指示第一同步源，确定单元1030具体用于：
根据第一同步信号确定至少一个同步源中包括第一同步源；
如果第一同步源满足预定义的条件，选择第一同步源为同步参考源；或者，
如果第一同步源的信号不满足预定义的条件，根据优先级信息选择至少一个同步源中除第一同步源外优先级最高的第二同步源为同步参考源。
可选地，第一同步信号包括第二同步信号和/或第三同步信号，确定单元1030具体用于：
根据第二同步信号的序列和/或第三同步信号的序列确定至少一个同步源的类型；
根据同步信息和至少一个同步源的类型确定同步参考源。
其中，第二同步信号的第一序列、第二序列、和第三序列分别用于指示不同的同步源类型，第一序列、第二序列和第三序列互不相同；或者，
第二同步信号占用第一符号和第二符号，第一符号使用的序列和第二符号使用的序列的多种组合方式用于指示不同的同步源类型；或者，
第三同步信号的序列集合包括多个序列子集，多个序列子集用于指示不同的同步源类型；或者，
第三同步信号占用第三符号和第四符号，第三符号使用的序列和第四符号使用的序列的多种组合方式用于指示不同的同步源类型；或者，
第二同步信号占用第一符号和第二符号，第三同步信号占用第三符号和第四符号，第一符号使用的序列、第二符号使用的序列、第三符号使用的序列和第四符号使用的序列的多种组合方式用于指示不同的同步源类型。
可选地，收发单元1020还用于，接收至少一个同步源发送的第一控制信息。
相应地，确定单元1030具体用于：
根据第一控制信息确定至少一个同步源的类型；
根据同步信息、第一同步信号和至少一个同步源的类型确定同步参考源。
可选地，收发单元1020还用于，接收至少一个同步源发送的第一控制信息，第一控制信息包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否发送的指示信息、同步信号是否有效的指示信息、同步信号发送的时频位置的指示信息、同步源的 跳数的指示信息。
可选地，第一同步信号包括第二同步信号和/或第三同步信号，确定单元1030具体用于，根据第二同步信号的序列和/或第三同步信号的序列、以及第一控制信息确定至少一个同步源的类型。
可选地，获取单元1010具体用于，接收基站发送的同步信息。
可选地，收发单元1020还用于，在获取单元1010接收同步信息之前，向基站发送至少一个同步源的信息，以便基站根据至少一个同步源的信息确定同步信息。
可选地，收发单元1020还用于，根据同步参考源发送第四同步信号和/或第二控制信息，第四同步信号和/或第二控制信息用于指示同步参考源的类型。
可选地，确定单元1030还用于，确定同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差；收发单元1020还用于，根据同步参考源的定时基准和确定单元1030确定的定时偏差进行通信。
可选地，收发单元1020还用于，接收基站发送的定时偏差指示信息，定时偏差指示用于指示所示定时偏差；确定单元1030具体用于，根据收发单元接收到的定时偏差指示信息确定定时偏差。
可选地，获取单元1010还用于，获取另一链路的同步参考源的定时基准；确定单元1020具体用于，根据同步参考源的定时基准和另一链路的同步参考源的定时基准确定定时偏差。
应理解，根据本发明实施例的用户设备1000可对应于根据本发明实施例的同步方法300中的用户设备，并且用户设备1000中的各个单元/模块的上述和其它操作和/或功能分别为了实现图3的方法300的相应流程，为了简洁，在此不再赘述。
本发明实施例中，通过获取同步信息，根据同步信息和至少一个同步源发送的同步信号确定同步参考源，能够实现同步。
图11是根据本发明另一实施例的基站1100的示意性框图。如图11所示，基站1100包括确定单元1110和发送单元1120。
确定单元1110，用于向用户设备发送同步信息，同步信息包括以下信息中的至少一种：同步源的选择参数信息、同步源的指示信息、同步源的优先级信息，以使用户设备根据该同步信息确定同步参考源；
发送单元1120，用于向用户设备发送同步信息。
本发明实施例中，通过向用户设备发送同步信息，使得用户设备能够根据同步信息确定同步参考源，从而能够实现同步，保证了最佳的通信性能。
可选地，发送单元1120还用于，向用户设备发送控制信息，控制信息用于指示同步参考源的类型和/或标识。
可选地，发送单元1120还用于，向用户设备发送控制信息，控制信息可以包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否有效的指示信息、同步信号是否发送的指示、同步信号发送的时频位置的指示信息、同步源的跳数的指示信息。
可选地，基站1100还可以包括：接收单元1130。
接收单元1130，用于在发送单元1120向用户设备发送同步信息之前，接收用户设备发送的至少一个同步源的信息；
确定单元1110具体用于根据接收单元1130接收到的至少一个同步源的信息确定同步信息。
可选地，发送单元1120还用于向用户设备发送定时偏差指示信息，定时偏差指示信息用于指示用户设备的同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差。
应理解，根据本发明实施例的基站1100可对应于根据本发明实施例的同步方法800中的基站，并且基站1100中的各个单元/模块的上述和其它操作和/或功能分别为了实现图8的方法800的相应流程，为了简洁，在此不再赘述。
本发明实施例中，通过向用户设备发送同步信息，使得用户设备能够根据同步信息确定同步参考源，从而能够实现同步，保证了最佳的通信性能。
图12是根据本发明另一实施例的用户设备1200的示意性框图。如图12所示，用户设备1200包括：确定单元1210和发送单元1220。
确定单元1210，用于确定同步参考源，同步参考源的类型为GNSS、基站、用户设备中的任意一种；
发送单元1220，用于根据同步参考源发送同步信号，同步信号包括第一同步信号和/或第二同步信号，第一同步信号的序列和/或第二同步信号的序列用于指示同步参考源的类型。
本发明实施例中，当UE的同步参考源的类型为GNSS、基站、UE中的 任意一种时，用户设备发送的同步信号能够指示该同步参考源的类型，使得其他用户设备能够根据该同步信号确定同步参考源，从而能够实现同步，保证了最佳的通信性能。
其中，第一同步信号的至少一种序列用于指示同步参考源的类型；或者，
第一同步信号占用第一符号和第二符号，第一符号使用的序列和第二符号使用的序列的至少一种组合方式用于指示同步参考源的类型；或者，
第二同步信号的序列集合包括至少两个序列子集，至少两个序列子集中的至少一种子集用于指示同步参考源的类型；或者，
第二同步信号包括第三符号和第四符号，第三符号使用的序列和第四符号使用的序列的至少一种组合方式用于指示同步参考源的类型；或者，
第一同步信号占用第一符号和第二符号，第二同步信号占用第三符号和第四符号，第一符号使用的序列、第二符号使用的序列、第三符号使用的序列和第四符号使用的序列的至少一种组合方式用于指示同步参考源的类型。
可选地，发送单元1220还用于，发送控制信息，第一同步信号的序列和/或第二同步信号的序列、以及控制信息用于指示同步参考源的类型。
可选地，发送单元1220还用于，发送控制信息，控制信息包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否有效的指示信息、同步信号是否发送的指示信息、同步信号发送的时频位置的指示信息、同步源的跳数的指示信息。
应理解，根据本发明实施例的用户设备1200可对应于根据本发明实施例的同步方法900中的用户设备，并且用户设备1200中的各个单元/模块的上述和其它操作和/或功能分别为了实现图9的方法900的相应流程，为了简洁，在此不再赘述。
本发明实施例中，当UE的同步参考源的类型为GNSS、基站、UE中的任意一种时，用户设备发送的同步信号能够指示该同步参考源的类型，使得其他用户设备能够根据该同步信号确定该同步参考源的类型，从而能够实现同步，保证了最佳的通信性能。
图13是根据本发明另一实施例的用户设备1300的示意性框图。如图13所示，用户设备1300包括处理器1310、存储器1320、总线系统1330和收发器1340。其中，处理器1310、存储器1320和收发器1340通过总线系统1330相连，该存储器1320用于存储指令，该处理器1310用于执行该存储器 1320存储的指令。
其中，处理器1310用于获取同步信息，同步信息包括以下信息中的至少一种：同步源的选择参数信息、同步源的指示信息、同步源的优先级信息；
收发器1340，用于接收至少一个同步源发送的第一同步信号；
处理器1310还用于，根据同步信息和第一同步信号确定同步参考源。
本发明实施例中，通过获取同步信息，根据同步信息和至少一个同步源发送的同步信号确定同步参考源，能够实现同步。
应理解，在本发明实施例中，该处理器1310可以是中央处理单元(Central Processing Unit，简称CPU)，该处理器1310还可以是其他通用处理器、数字信号处理器(Digital Signal Processing，简称DSP)、专用集成电路(Application Specific Integrated Circuit，简称ASIC)、现场可编程门阵列(Field-Programmable Gate Array，简称FPGA)或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件等。通用处理器可以是微处理器或者该处理器也可以是任何常规的处理器等。
该存储器1320可以包括只读存储器和随机存取存储器，并向处理器1310提供指令和数据。存储器1320的一部分还可以包括非易失性随机存取存储器。例如，存储器1320还可以存储设备类型的信息。
该总线系统1330除包括数据总线之外，还可以包括电源总线、控制总线和状态信号总线等。但是为了清楚说明起见，在图中将各种总线都标为总线系统1330。
在实现过程中，上述方法的各步骤可以通过处理器1310中的硬件的集成逻辑电路或者软件形式的指令完成。结合本发明实施例所公开的方法的步骤可以直接体现为硬件处理器执行完成，或者用处理器中的硬件及软件模块组合执行完成。软件模块可以位于随机存储器、闪存、只读存储器、可编程只读存储器或者电可擦写可编程存储器、寄存器等本领域成熟的存储介质中。该存储介质位于存储器1320，处理器1310读取存储器1320中的信息，结合其硬件完成上述方法的步骤。为避免重复，这里不再详细描述。
可选地，收发器1340还用于接收基站发送的同步信息。相应地，处理器1310从收发器1340获取同步信息。
可选地，处理器1310具体用于，根据第一同步信号选择至少一个同步源中满足选择参数的同步源作为同步参考源。
可选地，同步源的指示信息用于指示第一同步源，处理器1310具体用于，根据第一同步信号选择第一同步源为同步参考源。
可选地，处理器1310具体用于，用户设备根据优先级信息和第一同步信号选择至少一个同步源中优先级最高的同步源为同步参考源。
可选地，同步源的指示信息用于指示第一同步源。
相应地，处理器1310具体用于：
根据第一同步信号确定至少一个同步源中包括第一同步源；
如果第一同步源满足预定义的条件，选择第一同步源为同步参考源；或者，
如果第一同步源的信号不满足预定义的条件，根据优先级信息选择至少一个同步源中除第一同步源外优先级最高的第二同步源为同步参考源。
可选地，第一同步信号包括第二同步信号和/或第三同步信号，处理器1310具体用于：
根据第二同步信号的序列和/或第三同步信号的序列确定至少一个同步源的类型；
根据同步信息和至少一个同步源的类型选择同步参考源。
其中，第二同步信号的第一序列、第二序列、和第三序列分别用于指示不同的同步源类型，第一序列、第二序列和第三序列互不相同；或者，
第二同步信号占用第一符号和第二符号，第一符号使用的序列和第二符号使用的序列的多种组合方式用于指示不同的同步源类型；或者，
第三同步信号的序列集合包括多个序列子集，多个序列子集用于指示不同的同步源类型；或者，
第三同步信号占用第三符号和第四符号，第三符号使用的序列和第四符号使用的序列的多种组合方式用于指示不同的同步源类型；或者，
第二同步信号占用第一符号和第二符号，第三同步信号占用第三符号和第四符号，第一符号使用的序列、第二符号使用的序列、第三符号使用的序列和第四符号使用的序列的多种组合方式用于指示不同的同步源类型。
可选地，收发器1340还用于接收至少一个同步源发送的第一控制信息。
相应地，处理器1310具体用于：
根据第一控制信息确定至少一个同步源的类型；
根据同步信息、第一同步信号和至少一个同步源的类型确定同步参考 源。
可选地，收发器1340还用于，接收至少一个同步源发送的第一控制信息，第一控制信息包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否发送的指示信息、同步信号是否有效的指示信息、同步信号发送的时频位置的指示信息、同步源的跳数的指示信息。
可选地，第一同步信号包括第二同步信号和/或第三同步信号，处理器1310具体用于，根据第二同步信号的序列和/或第三同步信号的序列、以及第一控制信息确定至少一个同步源的类型。
可选地，收发器1340还用于，在接收同步信息之前，向基站发送至少一个同步源的信息，以便基站根据至少一个同步源的信息确定同步信息。
可选地，收发器1340还用于，根据同步参考源发送第四同步信号和/或第二控制信息，第四同步信号和/或第二控制信息用于指示同步参考源的类型。
可选地，处理器1310还用于，确定同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差；收发器1340还用于，根据同步参考源的定时基准和处理器1310确定的定时偏差进行通信。
可选地，收发器1340还用于，接收基站发送的定时偏差指示信息，定时偏差指示用于指示所示定时偏差；处理器1310具体用于，根据收发器1340接收到的定时偏差指示信息确定定时偏差。
可选地，处理器1310还用于获取另一链路的同步参考源的定时基准；处理器1310具体用于，根据同步参考源的定时基准和另一链路的同步参考源的定时基准确定定时偏差。
应理解，根据本发明实施例的用户设备1300可对应于根据本发明实施例的同步方法300中的用户设备以及根据本发明实施例的用户设备1000，并且用户设备1300中的各个单元/模块的上述和其它操作和/或功能分别为了实现图3的方法300的相应流程，为了简洁，在此不再赘述。
本发明实施例中，通过获取同步信息，根据同步信息和至少一个同步源的同步信号确定同步参考源，能够实现同步。
图14是根据本发明另一实施例的基站1400的示意性框图。如图14所示，基站1400包括处理器1410、存储器1420、总线系统1430和收发器1440。 其中，处理器1410、存储器1420和收发器1440通过总线系统1430相连，该存储器1420用于存储指令，该处理器1410用于执行该存储器1420存储的指令。
其中，处理器1410用于确定同步信息，同步信息包括以下信息中的至少一种：同步源的选择参数信息、同步源的指示信息、同步源的优先级信息；
收发器1440，用于向用户设备发送同步信息。
本发明实施例中，通过向用户设备发送同步信息，使得用户设备能够根据同步信息确定同步参考源，从而能够实现同步，保证了最佳的通信性能。
应理解，在本发明实施例中，该处理器1410可以是CPU，该处理器1410还可以是其他通用处理器、DSP、ASIC、FPGA或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件等。通用处理器可以是微处理器或者该处理器也可以是任何常规的处理器等。
该存储器1420可以包括只读存储器和随机存取存储器，并向处理器1410提供指令和数据。存储器1420的一部分还可以包括非易失性随机存取存储器。例如，存储器1420还可以存储设备类型的信息。
该总线系统1430除包括数据总线之外，还可以包括电源总线、控制总线和状态信号总线等。但是为了清楚说明起见，在图中将各种总线都标为总线系统1430。
在实现过程中，上述方法的各步骤可以通过处理器1410中的硬件的集成逻辑电路或者软件形式的指令完成。结合本发明实施例所公开的方法的步骤可以直接体现为硬件处理器执行完成，或者用处理器中的硬件及软件模块组合执行完成。软件模块可以位于随机存储器、闪存、只读存储器、可编程只读存储器或者电可擦写可编程存储器、寄存器等本领域成熟的存储介质中。该存储介质位于存储器1420，处理器1410读取存储器1420中的信息，结合其硬件完成上述方法的步骤。为避免重复，这里不再详细描述。
可选地，收发器1440还用于，向用户设备发送控制信息，控制信息用于指示同步参考源的类型和/或标识。
可选地，收发器1440还用于，向用户设备发送控制信息，控制信息包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否有效的指示信息、同步信号是否发送的指示信息、同步信号发送的时频位置的指示信息、同步源的跳数的指示信息。
可选地，收发器1440还用于，在向用户设备发送同步信息之前，接收用户设备发送的至少一个同步源的信息；处理器1410，用于根据收发器1440接收到的至少一个同步源的信息确定同步信息。
可选地，收发器1440还用于，向用户设备发送定时偏差指示信息，定时偏差指示信息用于指示用户设备的同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差。
应理解，根据本发明实施例的基站1400可对应于根据本发明实施例的同步方法800中的基站以及根据本发明实施例的基站1100，并且基站1400中的各个单元/模块的上述和其它操作和/或功能分别为了实现图8的方法800的相应流程，为了简洁，在此不再赘述。
本发明实施例中，通过向用户设备发送同步信息，使得用户设备能够根据同步信息确定同步参考源，从而能够实现同步，保证了最佳的通信性能。
图15是根据本发明另一实施例的用户设备1500的示意性框图。如图15所示，用户设备1500包括处理器1510、存储器1520、总线系统1530和发送器1540。其中，处理器1510、存储器1520和发送器1540通过总线系统1530相连，该存储器1520用于存储指令，该处理器1510用于执行该存储器1520存储的指令。
其中，处理器1510，用于确定同步参考源，同步参考源的类型为全球卫星导航系统、基站、用户设备中的任意一种；
发送器1540，用于根据同步参考源发送同步信号，同步信号包括第一同步信号和/或第二同步信号，第一同步信号的序列和/或第二同步信号的序列用于指示同步参考源的类型。
本发明实施例中，当UE的同步参考源的类型为GNSS、基站、UE中的任意一种时，用户设备发送的同步信号能够指示该同步参考源的类型，使得其他用户设备能够根据该同步信号确定该同步参考源的类型，从而能够实现同步，保证了最佳的通信性能。
应理解，在本发明实施例中，该处理器1510可以是CPU，该处理器1510还可以是其他通用处理器、DSP、ASIC、FPGA或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件等。通用处理器可以是微处理器或者该处理器也可以是任何常规的处理器等。
该存储器1520可以包括只读存储器和随机存取存储器，并向处理器 1510提供指令和数据。存储器1520的一部分还可以包括非易失性随机存取存储器。例如，存储器1520还可以存储设备类型的信息。
该总线系统1530除包括数据总线之外，还可以包括电源总线、控制总线和状态信号总线等。但是为了清楚说明起见，在图中将各种总线都标为总线系统1530。
在实现过程中，上述方法的各步骤可以通过处理器1510中的硬件的集成逻辑电路或者软件形式的指令完成。结合本发明实施例所公开的方法的步骤可以直接体现为硬件处理器执行完成，或者用处理器中的硬件及软件模块组合执行完成。软件模块可以位于随机存储器、闪存、只读存储器、可编程只读存储器或者电可擦写可编程存储器、寄存器等本领域成熟的存储介质中。该存储介质位于存储器1520，处理器1510读取存储器1520中的信息，结合其硬件完成上述方法的步骤。为避免重复，这里不再详细描述。
其中，第一同步信号的至少一种序列用于指示同步参考源的类型；或者，
第一同步信号占用第一符号和第二符号，第一符号使用的序列和第二符号使用的序列的至少一种组合方式用于指示同步参考源的类型；或者，
第二同步信号的序列集合包括至少两个序列子集，至少两个序列子集中的至少一种子集用于指示同步参考源的类型；或者，
第二同步信号包括第三符号和第四符号，第三符号使用的序列和第四符号使用的序列的至少一种组合方式用于指示同步参考源的类型；或者，
第一同步信号占用第一符号和第二符号，第二同步信号占用第三符号和第四符号，第一符号使用的序列、第二符号使用的序列、第三符号使用的序列和第四符号使用的序列的至少一种组合方式用于指示同步参考源的类型。
可选地，发送器1540还用于，发送控制信息，第一同步信号的序列和/或第二同步信号的序列、以及控制信息用于指示同步参考源的类型。
可选地，发送器1540还用于，发送控制信息，控制信息包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否有效的指示信息、同步信号是否发送的指示信息、同步信号发送的时频位置的指示信息、同步源的跳数的指示信息。
应理解，根据本发明实施例的用户设备1500可对应于根据本发明实施例的同步方法900中的用户设备以及根据本发明实施例的用户设备1200，并且用户设备1500中的各个单元/模块的上述和其它操作和/或功能分别为了 实现图9的方法900的相应流程，为了简洁，在此不再赘述。
本发明实施例中，当UE的同步参考源的类型为GNSS、基站、UE中的任意一种时，用户设备发送的同步信号能够指示该同步参考源的类型，使得其他用户设备能够根据该同步信号确定该同步参考源的类型，从而能够实现同步，保证了最佳的通信性能。
应理解，在本发明实施例中，术语“和/或”仅仅是一种描述关联对象的关联关系，表示可以存在三种关系。例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系。
本领域普通技术人员可以意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，能够以电子硬件、计算机软件或者二者的结合来实现，为了清楚地说明硬件和软件的可互换性，在上述说明中已经按照功能一般性地描述了各示例的组成及步骤。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本发明的范围。
所属领域的技术人员可以清楚地了解到，为了描述的方便和简洁，上述描述的系统、装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统、装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另外，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口、装置或单元的间接耦合或通信连接，也可以是电的，机械的或其它的形式连接。
作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本发明实施例方案的目的。
另外，在本发明各个实施例中的各功能单元可以集成在一个处理单元 中，也可以是各个单元单独物理存在，也可以是两个或两个以上单元集成在一个单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。
通过以上的实施方式的描述，所属领域的技术人员可以清楚地了解到本发明可以用硬件实现，或固件实现，或它们的组合方式来实现。当使用软件实现时，可以将上述功能存储在计算机可读介质中或作为计算机可读介质上的一个或多个指令或代码进行传输。计算机可读介质包括计算机存储介质和通信介质，其中通信介质包括便于从一个地方向另一个地方传送计算机程序的任何介质。存储介质可以是计算机能够存取的任何可用介质。以此为例但不限于：计算机可读介质可以包括RAM、ROM、EEPROM、CD-ROM或其他光盘存储、磁盘存储介质或者其他磁存储设备、或者能够用于携带或存储具有指令或数据结构形式的期望的程序代码并能够由计算机存取的任何其他介质。此外。任何连接可以适当的成为计算机可读介质。例如，如果软件是使用同轴电缆、光纤光缆、双绞线、数字用户线(英文Digital Subscriber Line，简称DSL)或者诸如红外线、无线电和微波之类的无线技术从网站、服务器或者其他远程源传输的，那么同轴电缆、光纤光缆、双绞线、DSL或者诸如红外线、无线和微波之类的无线技术包括在所属介质的定影中。如本发明所使用的，盘(Disk)和碟(disc)包括压缩光碟(CD)、激光碟、光碟、数字通用光碟(DVD)、软盘和蓝光光碟，其中盘通常磁性的复制数据，而碟则用激光来光学的复制数据。上面的组合也应当包括在计算机可读介质的保护范围之内。
总之，以上仅为本发明技术方案的较佳实施例而已，并非用于限定本发明的保护范围。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (50)

  1. 一种同步方法，其特征在于，包括：
    用户设备获取同步信息，所述同步信息包括以下信息中的至少一种：同步源的选择参数信息、同步源的指示信息、同步源的优先级信息；
    所述用户设备接收至少一个同步源发送的第一同步信号；
    所述用户设备根据所述同步信息和所述第一同步信号确定同步参考源。
  2. 根据权利要求1所述的方法，其特征在于，所述用户设备根据所述同步信息和所述第一同步信号确定同步参考源包括：
    所述用户设备根据所述第一同步信号选择所述至少一个同步源中满足所述选择参数信息的同步源作为所述同步参考源。
  3. 根据权利要求1所述的方法，其特征在于，所述同步源的指示信息用于指示第一同步源，所述用户设备根据所述同步信息和所述第一同步信号确定同步参考源，包括：
    所述用户设备根据所述第一同步信号选择所述第一同步源为所述同步参考源。
  4. 根据权利要求1所述的方法，其特征在于，所述用户设备根据所述同步配置信息和所述第一同步信号确定同步参考源包括：
    所述用户设备根据所述优先级信息和所述第一同步信号选择所述至少一个同步源中优先级最高的同步源为所述同步参考源。
  5. 根据权利要求1所述的方法，其特征在于，所述同步源的指示信息用于指示第一同步源，所述用户设备根据所述同步信息和所述第一同步信号确定同步参考源，包括：
    所述用户设备根据所述第一同步信号确定所述至少一个同步源中包括所述第一同步源；
    如果所述第一同步源满足预定义的条件，所述用户设备选择所述第一同步源为所述同步参考源；或者，
    如果所述第一同步源的信号不满足预定义的条件，所述用户设备根据优先级信息选择所述至少一个同步源中除所述第一同步源外优先级最高的第二同步源为所述同步参考源。
  6. 根据权利要求1至5中任一项所述的方法，其特征在于，所述第一 同步信号包括第二同步信号和/或第三同步信号，所述用户设备根据所述同步信息和所述第一同步信号确定同步参考源，包括：
    所述用户设备根据所述第二同步信号的序列和/或所述第三同步信号的序列确定所述至少一个同步源的类型；
    所述用户设备根据所述同步信息和所述至少一个同步源的类型确定所述同步参考源。
  7. 根据权利要求6所述的方法，其特征在于，
    所述第二同步信号的第一序列、第二序列、和第三序列分别用于指示不同的同步源类型，所述第一序列、所述第二序列和所述第三序列互不相同；或者，
    所述第二同步信号占用第一符号和第二符号，所述第一符号使用的序列和所述第二符号使用的序列的多种组合方式用于指示不同的同步源类型；或者，
    所述第三同步信号的序列集合包括多个序列子集，所述多个序列子集用于指示不同的同步源类型；或者，
    所述第三同步信号占用第三符号和第四符号，所述第三符号使用的序列和所述第四符号使用的序列的多种组合方式用于指示不同的同步源类型；或者，
    所述第二同步信号占用第一符号和第二符号，所述第三同步信号占用第三符号和第四符号，所述第一符号使用的序列、所述第二符号使用的序列、所述第三符号使用的序列和所述第四符号使用的序列的多种组合方式用于指示不同的同步源类型。
  8. 根据权利要求1至5中任一项所述的方法，其特征在于，还包括：
    所述用户设备接收所述至少一个同步源发送的第一控制信息；
    所述用户设备根据所述同步信息和所述第一同步信号确定同步参考源，包括：
    所述用户设备根据所述第一控制信息确定所述至少一个同步源的类型；
    所述用户设备根据所述同步信息、所述第一同步信号和所述至少一个同步源的类型确定所述同步参考源。
  9. 根据权利要求1至7中任一项所述的方法，其特征在于，还包括：
    所述用户设备接收所述至少一个同步源发送的第一控制信息，所述第一 控制信息包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否发送的指示信息、同步信号是否有效的指示信息、同步信号发送的时频位置的指示信息、同步源的跳数的指示信息。
  10. 根据权利要求8所述的方法，其特征在于，所述第一同步信号包括第二同步信号和/或第三同步信号，所述用户设备根据所述第一控制信息确定所述至少一个同步源的类型，包括：
    所述用户设备根据所述第二同步信号的序列和/或所述第三同步信号的序列、以及所述第一控制信息确定所述至少一个同步源的类型。
  11. 根据权利要求1至10中任一项所述的方法，其特征在于，所述接收端获取同步信息，包括：
    所述用户设备接收基站发送的所述同步信息。
  12. 根据权利要求11所述的方法，其特征在于，在所述用户设备接收所述同步信息之前，所述方法还包括：
    所述用户设备向所述基站发送所述至少一个同步源的信息，以便所述基站根据所述至少一个同步源的信息确定所述同步信息。
  13. 根据权利要求1至12中任一项所述的方法，其特征在于，还包括：
    所述用户设备根据所述同步参考源发送第四同步信号和/或第二控制信息，所述第四同步信号和/或所述第二控制信息用于指示所述同步参考源的类型。
  14. 根据权利要求1至13中任一项所述的方法，其特征在于，还包括：
    所述用户设备确定所述同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差；
    所述用户设备根据所述同步参考源的定时基准和所述定时偏差进行通信。
  15. 根据权利要求14所述的方法，其特征在于，所述用户设备确定所述同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差，包括：
    所述用户设备接收基站发送的定时偏差指示信息，所述定时偏差指示用于指示所示定时偏差；
    所述用户设备根据所述定时偏差指示信息确定所述定时偏差。
  16. 根据权利要求14所述的方法，其特征在于，所述用户设备确定所述同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差，包括：
    所述用户设备获取所述另一链路的同步参考源的定时基准；
    所述用户设备根据所述同步参考源的定时基准和所述另一链路的同步参考源的定时基准确定所述定时偏差。
  17. 一种同步方法，其特征在于，包括：
    基站确定同步信息，所述同步信息包括以下信息中的至少一种：同步源的选择参数信息、同步源的指示信息、同步源的优先级信息；
    基站向用户设备发送所述同步信息。
  18. 根据权利要求17所述的方法，其特征在于，还包括：
    所述基站向所述用户设备发送控制信息，所述控制信息用于指示所述同步参考源的类型和/或标识。
  19. 根据权利要求17所述的方法，其特征在于，还包括:
    所述基站向所述用户设备发送控制信息，所述控制信息包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否有效的指示信息、同步信号是否发送的指示信息、同步信号发送的时频位置的指示信息、同步源的跳数的指示信息。
  20. 根据权利要求17至19中任一项所述的方法，其特征在于，所述基站确定同步信息包括：
    所述基站接收所述用户设备发送的至少一个同步源的信息；
    所述基站根据所述至少一个同步源的信息确定所述同步信息。
  21. 根据权利要求17至20中任一项所述的方法，其特征在于，还包括：
    所述基站向所述用户设备发送定时偏差指示信息，所述定时偏差指示信息用于指示所述用户设备的同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差。
  22. 一种同步方法，其特征在于，包括：
    用户设备确定同步参考源，所述同步参考源的类型为全球卫星导航系统、基站、用户设备中的任意一种；
    所述用户设备根据所述同步参考源发送同步信号，所述同步信号包括第一同步信号和/或第二同步信号，所述第一同步信号的序列和/或所述第二同步信号的序列用于指示所述同步参考源的类型。
  23. 根据权利要求22所述的方法，其特征在于，
    所述第一同步信号的至少一种序列用于指示所述同步参考源的类型；或者，
    所述第一同步信号占用第一符号和第二符号，所述第一符号使用的序列和所述第二符号使用的序列的至少一种组合方式用于指示所述同步参考源的类型；或者，
    所述第二同步信号的序列集合包括至少两个序列子集，所述至少两个序列子集中的至少一种子集用于指示所述同步参考源的类型；或者，
    所述第二同步信号包括第三符号和第四符号，所述第三符号使用的序列和所述第四符号使用的序列的至少一种组合方式用于指示所述同步参考源的类型；或者，
    所述第一同步信号占用第一符号和第二符号，所述第二同步信号占用第三符号和第四符号，所述第一符号使用的序列、所述第二符号使用的序列、所述第三符号使用的序列和所述第四符号使用的序列的至少一种组合方式用于指示所述同步参考源的类型。
  24. 根据权利要求22或23所述的方法，其特征在于，还包括：
    所述用户设备发送控制信息，所述第一同步信号的序列和/或所述第二同步信号的序列、以及所述控制信息用于指示所述同步参考源的类型。
  25. 根据权利要求22或23所述的方法，其特征在于，还包括：
    所述用户设备发送控制信息，所述控制信息包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否有效的指示信息、同步信号是否发送的指示信息、同步信号发送的时频位置的指示信息、同步源的跳数的指示信息。
  26. 一种用户设备，其特征在于，包括：
    获取单元，用于获取同步信息，所述同步信息包括以下信息中的至少一种：同步源的选择参数信息、同步源的指示信息、同步源的优先级信息；
    收发单元，用于接收至少一个同步源发送的第一同步信号；
    确定单元，用于根据所述获取单元获取到的所述同步信息和所述收发单 元接收到的所述第一同步信号确定同步参考源。
  27. 根据权利要求26所述的用户设备，其特征在于，所述确定单元具体用于，根据所述第一同步信号选择所述至少一个同步源中满足所述选择参数信息的同步源作为所述同步参考源。
  28. 根据权利要求26所述的用户设备，其特征在于，所述同步源的指示信息用于指示第一同步源，
    所述确定单元具体用于，根据所述第一同步信号选择所述第一同步源为所述同步参考源。
  29. 根据权利要求26所述的用户设备，其特征在于，所述确定单元具体用于，所述用户设备根据所述优先级信息和所述第一同步信号选择所述至少一个同步源中优先级最高的同步源为所述同步参考源。
  30. 根据权利要求26所述的用户设备，其特征在于，所述同步源的指示信息用于指示第一同步源，所述确定单元具体用于：
    根据所述第一同步信号确定所述至少一个同步源中包括所述第一同步源；
    如果所述第一同步源满足预定义的条件，选择所述第一同步源为所述同步参考源；或者，
    如果所述第一同步源的信号不满足预定义的条件，根据优先级信息选择所述至少一个同步源中除所述第一同步源外优先级最高的第二同步源为所述同步参考源。
  31. 根据权利要求26至30中任一项所述的用户设备，其特征在于，所述第一同步信号包括第二同步信号和/或第三同步信号，
    所述确定单元具体用于：
    根据所述第二同步信号的序列和/或所述第三同步信号的序列确定所述至少一个同步源的类型；
    根据所述同步信息和所述至少一个同步源的类型确定所述同步参考源。
  32. 根据权利要求31所述的用户设备，其特征在于，
    所述第二同步信号的第一序列、第二序列、和第三序列分别用于指示不同的同步源类型，所述第一序列、所述第二序列和所述第三序列互不相同；或者，
    所述第二同步信号占用第一符号和第二符号，所述第一符号使用的序列 和所述第二符号使用的序列的多种组合方式用于指示不同的同步源类型；或者，
    所述第三同步信号的序列集合包括多个序列子集，所述多个序列子集用于指示不同的同步源类型；或者，
    所述第三同步信号占用第三符号和第四符号，所述第三符号使用的序列和所述第四符号使用的序列的多种组合方式用于指示不同的同步源类型；或者，
    所述第二同步信号占用第一符号和第二符号，所述第三同步信号占用第三符号和第四符号，所述第一符号使用的序列、所述第二符号使用的序列、所述第三符号使用的序列和所述第四符号使用的序列的多种组合方式用于指示不同的同步源类型。
  33. 根据权利要求26至30中任一项所述的用户设备，其特征在于，所述收发单元还用于，接收所述至少一个同步源发送的第一控制信息；
    所述确定单元具体用于：
    根据所述第一控制信息确定所述至少一个同步源的类型；
    根据所述同步信息、所述第一同步信号和所述至少一个同步源的类型确定所述同步参考源。
  34. 根据权利要求26至32中任一项所述的用户设备，其特征在于，所述收发单元还用于，接收所述至少一个同步源发送的第一控制信息，所述第一控制信息包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否发送的指示信息、同步信号是否有效的指示信息、同步信号发送的时频位置的指示信息、同步源的跳数的指示信息。
  35. 根据权利要求33所述的用户设备，其特征在于，所述第一同步信号包括第二同步信号和/或第三同步信号，
    所述确定单元具体用于，根据所述第二同步信号的序列和/或所述第三同步信号的序列、以及所述第一控制信息确定所述至少一个同步源的类型。
  36. 根据权利要求26至35中任一项所述的用户设备，其特征在于，所述获取单元具体用于，接收基站发送的所述同步信息。
  37. 根据权利要求36所述的用户设备，其特征在于，所述收发单元还用于，在所述获取单元接收所述同步信息之前，向所述基站发送所述至少一 个同步源的信息，以便所述基站根据所述至少一个同步源的信息确定所述同步信息。
  38. 根据权利要求26至37中任一项所述的用户设备，其特征在于，所述收发单元还用于，根据所述同步参考源发送第四同步信号和/或第二控制信息，所述第四同步信号和/或所述第二控制信息用于指示所述同步参考源的类型。
  39. 根据权利要求26至38中任一项所述的用户设备，其特征在于，
    所述确定单元还用于，确定所述同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差；
    所述收发单元还用于，根据所述同步参考源的定时基准和所述确定单元确定的所述定时偏差进行通信。
  40. 根据权利要求39所述的用户设备，其特征在于，
    所述收发单元还用于，接收基站发送的定时偏差指示信息，所述定时偏差指示用于指示所示定时偏差；
    所述确定单元具体用于，根据所述收发单元接收到的所述定时偏差指示信息确定所述定时偏差。
  41. 根据权利要求39所述的用户设备，其特征在于，
    所述获取单元还用于，获取所述另一链路的同步参考源的定时基准；
    所述确定单元具体用于，根据所述同步参考源的定时基准和所述另一链路的同步参考源的定时基准确定所述定时偏差。
  42. 一种基站，其特征在于，包括：
    确定单元，用于确定同步信息，所述同步信息包括以下信息中的至少一种：同步源的选择参数信息、同步源的指示信息、同步源的优先级信息；
    发送单元，用于向用户设备发送所述同步信息。
  43. 根据权利要求42所述的基站，其特征在于，所述发送单元还用于，向所述用户设备发送控制信息，所述控制信息用于指示所述同步参考源的类型和/或标识。
  44. 根据权利要求42所述的基站，其特征在于，还包括：
    所述基站向所述用户设备发送控制信息，所述控制信息包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否有效的指示信息、同步信号是否发送的指示信息、同步信号发 送的时频位置的指示信息、同步源的跳数的指示信息。
  45. 根据权利要求42至44中任一种所述的基站，其特征在于，还包括：
    接收单元，用于在所述发送单元向所述用户设备发送所述同步信息之前，接收所述用户设备发送的至少一个同步源的信息；
    所述确定单元具体用于，根据所述接收单元接收到的所述至少一个同步源的信息确定所述同步信息。
  46. 根据权利要求42至45中任一项所述的基站，其特征在于，
    发送单元还用于，向所述用户设备发送定时偏差指示信息，所述定时偏差指示信息用于指示所述用户设备的同步参考源的定时基准与另一链路的同步参考源的定时基准之间的定时偏差。
  47. 一种用户设备，其特征在于，包括：
    确定单元，用于确定同步参考源，所述同步参考源的类型为全球卫星导航系统、基站、用户设备中的任意一种；
    发送单元，用于根据所述同步参考源发送同步信号，所述同步信号包括第一同步信号和/或第二同步信号，所述第一同步信号的序列和/或所述第二同步信号的序列用于指示所述同步参考源的类型。
  48. 根据权利要求47所述的用户设备，其特征在于，
    所述第一同步信号的至少一种序列用于指示所述同步参考源的类型；或者，
    所述第一同步信号占用第一符号和第二符号，所述第一符号使用的序列和所述第二符号使用的序列的至少一种组合方式用于指示所述同步参考源的类型；或者，
    所述第二同步信号的序列集合包括至少两个序列子集，所述至少两个序列子集中的至少一种子集用于指示所述同步参考源的类型；或者，
    所述第二同步信号包括第三符号和第四符号，所述第三符号使用的序列和所述第四符号使用的序列的至少一种组合方式用于指示所述同步参考源的类型；或者，
    所述第一同步信号占用第一符号和第二符号，所述第二同步信号占用第三符号和第四符号，所述第一符号使用的序列、所述第二符号使用的序列、所述第三符号使用的序列和所述第四符号使用的序列的至少一种组合方式用于指示所述同步参考源的类型。
  49. 根据权利要求47或48所述的用户设备，其特征在于，所述发送单元还用于，发送控制信息，所述第一同步信号的序列和/或所述第二同步信号的序列、以及所述控制信息用于指示所述同步参考源的类型。
  50. 根据权利要求47或48所述的用户设备，其特征在于，所述发送单元还用于，发送控制信息，所述控制信息包括以下信息中的至少一种：同步源的类型辅助指示信息、同步信号的发送周期的指示信息、同步信号是否有效的指示信息、同步信号是否发送的指示信息、同步信号发送的时频位置的指示信息、同步源的跳数的指示信息。
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